I need to move large sections of the map, can't figure out how.

I want to move thousands of entities/brushes, there is no way I can do it all one by one, slowly CTRL clicking.
I’m pretty sure there was a way to make a large selection, but I can’t remember how. I have spent hours trying to google for an answer :confused:
If you know how, I’ll love you forever <3… Forever is a long time, but maybe for like 20 minutes? sounds good? good!

In the grid make a big cube with the selection tool, then press enter.