how to decomply map?

before you compile see if you can get the vmf off the level creator, it’s better than a broken decompilied map
if you have no luck and the map creator hasn’t said you can’t decompile his map anyway, use bspsrc you will still get errors in the decompilied vmf which will need fixing 1st before any thing you intend to do

It was my old project so i need to decomply but how?