Is there a map, or how do you find your house if you get lost?

No there isn't but if u fly up until u die u get spawned to the place u started first in the world

You can use the compass to find your first spawning place. If you add the magnet to your other places you can find the nearest magnet to your current place.

You can make a map at minecraft using canvas and compass and putting them at table but I tried several time at mini block croft and it did not work.

I put signs which made from light and block and tableau on top of the montains to find places. I put names on places as we do at real life.

There is a compass. It will lead you to the spot where you first spawned. Hopefully you built near that.