Yes, I'll try to help. Others may come along with different techniques and advice. First, make your Page Size something like 80x120 units , choose either 5' per unit (newer games of D&D and PF), or 10' per unit (old school D&D this is a common option). This will give you a nice field to work with. Usually something like a large building, cathedral, church, small keep, should easily fit on this map with a yard, courtyard, garden, woods, pond, or wilderness to spare on the outside. It is possible to go larger but larger sizes than this would be more like a substantial battlefield or acreage of wilderness, or perhaps a larger castle (then try perhaps 150x180 units, or more). Make your background green (grass) or brown (ground). Now turn OFF the grid (makes it easier to place a map). Switch to Map layer. Keep Zoom at 100% at first (sometimes helps with dropping the map graphic). Place your map's main graphic / background / the map. Zoom out to about 30%. Now stretch your map out to a good large size on your field. This is where you would use 'Set Diminsions' of your graphic. Is it a square graphic or a vertical? Try setting something like 50x70 units at first. Or use the "handles" (the little corners to drag and stretch the size). Switch to the Ruler tool. Now use the Ruler tool to measure something know-able in your map, such as a Table, or the width of a hallway. Are you happy that a hallway is now showing as, perhaps 7' wide or 10' wide or 12' wide? Is your table in the great-hall around 8' long? Is your Fireplace around 5' to 7' wide? Is a chair showing around 2' to 3' or something you consider reasonable? That's a good technique especially if you're making a map that has indoors, tables, hallways. I usually do all of the above, before turning on the Grid. When you're finished sizing it without Grid, then turn on the grid at your preferred settings and set the opacity to what you like. Once the grid is on, you can double-check again and confirm that the building is sized reasonably to what you would expect for measurable elements within the graphic. Wiki Docs that may help, <a href="https://wiki.roll20.net/Manipulating_Graphics" rel="nofollow">https://wiki.roll20.net/Manipulating_Graphics</a>
