SO, ABOUT TILESETS...

There are plenty of templates you can use for RM tile sets in making your own, but luckily RPG Maker, especially MV, comes pre-packaged with all the tilesets you need to make a game. You really don't need anything else, but if you do that's what the tile set DLC is for. For your first project, you need to start small. Unless you have serious artistic skill or money for commissions, I highly recommend sticking with the base assets when starting out, especially the ones with MV as they're some of the highest quality assets I've seen, especially the OST. MV's OST might actually be one of the best in gaming, bar none. It's that good. If you run out, you can always use rips as long as your game is free. It's very unlikely the companies will go after you unless you directly compete with their product, like with AM2R. (A fanmade Metroid 2 remake when Nintendo was about to come out with their own official one.) You can find plenty of good rips on The Spriter's Resource or for sound effects you can use The Sounds Resource. Ripped music can be easily found on YouTube, (use a Youtube to mp3 converter) Kinsider, (missing a lot of music tho due to various C&Ds) and Zohar's domain. (missing a lot of modern OSTs)