I'm completely new to Solarus, and I'd like to get some info on where to find tilesets, and other related stuff. Any help with this would be greatly appreciated.
The Solarus website has all you need to get started. I'm sure there are plenty of other websites that have free assets and such; or even paid assets.
You could try looking at itch.io for some stuff. I have used a few things from there for prototype artwork.
Some help and resources here: https://www.solarus-games.org/en/development