Welcome to the forum. I don't have an M1A but hopefully someone on here can help you with your inquiry. I'm guessing you've already tried the Youtube/Rumble route and googled for information.
Been there and done that. It's a wise person who realizes they don't really know how to do something before they undertake the project and will take the time to gather the needed information and knowledge ahead of time. Some mistakes are just frustrating, others can be expensive. Hopefully we learn from our mistakes and hence won't repeat them.So even if something looks simple, read the manual or watch videos on how it is done. Luckily it's a simple piece to replace.