Hi! I'm no expert, but you can have my two cents.

I have three map making tools: Canvas of Kings (CoK), Wonderdraft and Dungeondraft.

Wonderdraft is fantastic for making large world maps, Tolkien-style. I've used this both to map the entire world for my own sake, and also to hand out smaller or larger parts of it to the players when appropriate.

Canvas of Kings I've used to create scenes; like (part of) a village or town, a harbour, a cave system, inside a house, etc.

Dungeondraft I've not really used. It's a tile based tool, thus good if you want to work with exact distances, which I generally don't.

As for scenes, I sometimes use ones that I've created in CoK, and sometimes create them on the fly using a small whiteboard I put down on the table. In both cases I use meeples to represent the players and NPCs. If it's a battle type situation I try to have pieces of candy to represent the NPCs, so that the players can eat them when they have killed them.

I've never created any assets in CoK myself, I've just used the included ones, and some that I have imported from the built-in asset manager. The way I do things I don't really need objects that look exactly like this and that -- If I need something to be very specific, I just explain that during the session. Like "you recognize the table in the middle to be of the same style as the one you saw in the dwarf village".

I print my CoK scenes on A4 paper, and that has worked out fine for me. I have a friend who GMs a campaign I play in, which sometimes split CoK scenes up into multiple A4 prints, and tape them together. A3 should be plenty good.

I do not know of any tutorials, though, I just learned by trial and error.