Best compatibility for a MacBook Air early 2015 11 in laptop?

Hello! I just completely destroyed my laptop’s screen in class last week but my friend has graciously offered me her old MacBook Air to use for the time being. I need help deciding what’s the best move for the laptop considering there’s only 4 GB of memory on there.

I found out about Open Core Legacy Patch today but I am completely clueless when it comes to computers. I tried going on the website through safari and chrome but it keeps saying the connection is not private. When I’m able to bypass that message, I don’t know how to download the open core app. I attached an image on how it looks on my end but I’m completely lost. Is there anything I need to do so the website can look…normal? The loading bubble just stays the same. Someone please give any advice or really thorough videos I can watch to grasp how to get this laptop running? I need as much help as I can get.