It’s as simple of finding out how to download a local copy of any media or software you want to store for safekeeping, ideally with backups on a separate drive/machine.

Some good places to start would be linux ISOs and Wikipedia (both are freely distributed and quite useful im times of need), but obviously for any media secured by a paywall or not meant for us to “own”, you’ll have to find your own path. Probably would be worth checking the piracy lemmy comm.

Personally, I archive everything. I stream nothing.