FOSS gamedev and creative worlds

Hello everyone. I'm running the latest version of minetest on Umbutu Mate. I'm not the most tech savvy but I really wanted to take advantage of the mods. I'm know this problem has been covered but I'm not finding anything specific. The error reads
ModError: Error loading mod "dream builder": mod_name does not fo;;ow naming conventions: Only characters [a-z0-9] are allowed. Check debug.txt for details.

Don't know where to go with this. I don't even know where to find the debug.txt file.

This may seem simple to most but I'm completely lost.

I think I ran into that. Try taking '-master' off of the end of the folder names.

Rename to something like "dreambuilder" without "-master" and with no spaces.

nope. Didnt work. I can see it in the configuration screen, but then just errors out and won't even open the game. I delete the mod folder and it returns to normal. Would be nice for my son and I to have some mods to play with instead of just digging holes for coal and sand.