FOSS gamedev and creative worlds

i want to use the simple mobs but i was told the reason why its not working is because of some api file that doesnt work in 0.4.3. I was told I need to get git/development to make the small mobs work. the only thing is idk what git/development is so can someone provide a link? and also i wanted to install the animals mod but i cant get it to work

http://sfan.sf.funpic.de/minetest-builds/c55/minetest-0.4.3-25cf375-win32.7z
You'll have to use 7-zip to extract .7z files, though.

yay everything works now ty very much one last thing how do i get the sound to work? because this game is fun but its a bit dull with no sound