Are you talking about the actual rectangular deck on the dashboard or like the speakers and shit?
For the deck, there's generally 2 types of swaps, and for the simplest type replacing the deck front panel on the dashboard is literally the press of a button, you pull it off, and click the new one in. The slightly harder type is one you extract the whole unit out, which is harder because you might need to do some (relatively simple) rewiring. You can absolutely do it yourself with a youtube video and a wire stripper (and a screwdriver).
Here's a video I found, there's probably lots of these tutorials on yt
