Where would I find the brushes? Like brush models?

Sorry that came out a bit mean but I think the cause of my map not working as there is a error named ERROR: Max verts per brush (512) exceeded

You act like I have no idea how to use mod tools i'm pretty experienced but this may be my second corrupted map

I have tried almost everything, don't say I didn't save I have plently of times I just compile it and the changes I made are not even there.
EX if I remove something save then compile it would still be there.
Please help ive been working on this map for so long and don't want to restart

hey there is a bug in after life you can die when in after life also spawn points you can spawn where zombies cant get then pushed off