No worries, it's super easy once you know about it. Archive.org has been archiving websites since the mid 1990s, periodically "crawling" websites available on the internet to save them. I've found very few websites that weren't archived by them at least once if the site was up for more than a year or two.

I've started checking to make sure most of the links I share here on here are archived there first so if they do go dead we've got a backup. To check, just go to archive.org and paste the link in the top box (titled "Wayback Machine") and hit enter. If it's been archived, a bar graph will show up along the top with the dates it was archived. If not, it will offer you to let it archive it by just clicking a button (I believe it says "archive this page")