Playing Complete Homebrew Games

I've been building a Tabletop How to Train Your Dragon game for a few years, everything from armor, weapons and structures to 100+ illustrated dragon stat pages. I've had some setbacks due to hard drive failures, but in the future I want to make a fully-illustrated pdf game. In the meantime i can re-type a workable text file, but would that be usable here? I've only seen this site used once, and I'm a bit rusty overall with DnD, so this'll take some getting used to.

Custom character sheets are a pro feature.

Character sheets are made from HTML/CSS/JavaScript, not PDFs. You could certainly create one (although as Fabian mentions, creating a custom character sheet for your own campaign requires that the campaign creator be a Pro subscriber), of course, but you can't simply upload a PDF and get a pretty character sheet out of it.

Oh, yes the PDF I was taking about would be for later/interpersonal use, something to be emailed to players perhaps and not necessarily with this site. Sadly I am not versed in any form of coding, so that might have to wait. I'm fairly hopeless with anything more advanced than troubleshooting wifi.

You can play a home brew game without character sheets. You just use the Attributes and Abilities tab and the Default Roll Template to format it. That should get you off the ground.