Need some info on Customization

So I am really new to this platform and DnD in general. Me and 4 friends bought the Storm King's Thunder Game, and I am the DM. The game in itself is working great so far, but I am confused on most of the customization things. So I want to make a custom map for my friends which isn't originally part of the adventure, and I was wondering if there was a way to import a map onto my game. My googling suggest this is doable but I can't figure out how, or how to make a drawing I make myself 'compatible' with roll20. The second thing is for custom monsters. I have made my own monster, as an NPC, and have it fully fleshed out, except for the token. The token I want is kind of specific and my adventure, Storm King, doesn't have the token I am looking for. I have so far not found a way in which I can import an image and use that as a token. I have been able to change the 'avatar' of my monster but not the 'custom token'. I have only found out that I can use already existing tokens, tokens that are already in the adventure. And after I get the right token, is it then as easy as dragging the monster out of the journals and onto my map?

You can add any graphic you want (map token, etc.) to your game simply by dragging it from your desktop onto the window, or using the "Upload" button in your library. Once you get your token all set up and defined as the default token for a monster (must be the last step after all customization), then yeah, you can just drag the monster onto your map and it's ready to go. Here are instructions on linking tokens to journals (it can be tricky, so read thoroughly, here's a video if you'd rather learn that way.) Here are instructions on creating a new page and its map. [ Page Toolbar ] [ Page Settings ] [ Hints on aligning maps ] It also probably wouldn't hurt to quickly review the nature of the several layers of the tabletop area if you aren't already familiar with them. There is nothing in a module that you couldn't do manually yourself, (given a huge amount of time). Feel free to ask any questions.

Custom maps are easy. Click on the blue tab at the top right corner of the map area in the game, create a new page, click on that page (you might want to go into it's properties and disable the grid for now), then drag and drop your map (Make sure it is within the limitations of the art asset size. 5MB or less for your account tier) then adjust to fit the page.

Also, you talked about graphic compatibility. There's a whole wiki page on that, but in general: Tokens are best saved as PNGs with a transparent background. 140 pixels per intended grid unit is a common size. Make their overall file dimensions square (140x140 px) to avoid having them distort. Maps are best saved as jpegs. Again 140px per grid unit should give you more than enough resolution for most play. Try to keep the compression as high as you think still looks good for the smallest file size/best performance. Really huge maps are better done in sections. Use ".jpg" as the extension on jpegs, instead of ".jpeg". Roll20 doesn't understand the latter. If your map ends in ".jpeg", you can just change the extension; no need to re-save.

Those were some good articles but they still don't answer my question about tokens. It says that in step 2 that I need to have a token on the board, which I can't since I want a custom one. You talked about getting a 140x140 pic, but you didn't explain how to make it a token. All I have at the moment is an image for my creature in my saved gallery, and the thing that I don't know how to do is make that image the token for my character. Thanks for all the help and links regardless.

I think I got the tokens worked out now, so disregard that part of my last post. I would like to know more of how to make a custom map though. Is there a good way to make a map that looks passable, or any place that has preset templates that are free? And is it really so easy as to just drag the image of the map or the file onto the board and it snaps into place? And with passable I just mean something that looks fairly good, hopefully better than I can do with just paintbrushes with a computer mouse. Thanks for the help!

Do a web search, there are all kinds of map images out there for free.  There are reddit channels with nothing (almost) except maps.  There are youtube tutorials on making your own maps of just about any kind you want.  There are websites about mapping, or resources for mapping.  There are various tools for creating maps (some free, some not) that might be of interest, depending on exactly what you are looking for...  And what you need/want will probably be different if you are doing most things underground (traditional dungeon crawling), towns/cities, or region/continent/world maps. As far as placing a map on the page, it isn't quite that simple.  The map page can't read the info of your image to know what size to make it, so it is best if you know the dimensions of the image in pixels.  Then you can right click on your map image and set the dimensions manually once it is on the page. 

If you are willing to purchase marketplace packages, there are maps to be found in the Marketplace also. Those are already preset for Roll20 so when you use the Addon menu (if they are addons), they automatically get added to your map pages.

Also, You can build maps piece by piece in Roll20 if you have tiles or furniture-type graphics, but you will usually get beter performance from a single image assembled outside the game and uploaded as a unit. 

Sorry for not answering on this page in so long, but thank you all for your tips. Kraynic, I will do as you said and hopefully be able to create more maps (already have one custom, though I didn't do very much of it). Is there any particular guide or video or just information that you may be able to link me? I really want to be a good DM and I feel like creating my own content is a big step on the way of becoming more invested and making a better story for my players.