Go to the general modding forum, look for the thread called newbie questions look no further 2, and one of the last posts by me was how to do this.

i don't know where is we general mods forum could you help me

Oops - very sorry, i meant the general editing forum - out of guilt here is a link to the direct page your require, it is the last post (at the bottom) and says 'to make bases destrucable'.

To be honest, it could go on all day about what to do with things, basically save any files you will edit so that you have a 'backup' , then start editing. If it all goes pear shaped, rather than remembering what you did, you can just restore stuff and start again. Have fun, but be persistant with it. If you find yourself staring at the desktop - have another go. If you are still staring at desktop after four/five goes, copy what you did into the thread this link takes you too - and i will help. The reason to copy is so that i (or anyone else who answers) can see what you have done. One word of warning thouhg - i will be gone til tuesday very shortley - so i might not reply. Am sure someone else will step in to help out though!!
Good luck
Chips

General Editing forum - Newbie Questions?? Look no further 2!!