I am aware that there's a lifting basics post on the sidebar, however the question I have is yet to be answered.

As a guy who's never been to the gym before and has had no interest in going, should I just go in and follow a 5x5 worksheet I saw on the internet or should I stretch out and jog/walk first to warm up and then follow the worksheet?

Link to the worksheet: https://stronglifts.com/5x5/#Quick_Overview