I’ve worked as an assistant a few times and it included:

• lugging gear
• running wires for lights, monitors, power, etc.
• wrangling people so they’re ready for the next shot
• positioning lights, repositioning lights, re-repositioning lights
• holding reflectors… usually in the wrong spot
• blocking lights from windows
• monitoring gear to assure we have sufficient charge, memory, audio levels, etc.

Doing what you’re told quickly and with little explanation is the minimal expectation. Being able to do as much as possible without supervision is what makes you valuable.

Decide what the purpose of each photo is: art, documentation, family memories, portraits, etc. Then you know how to treat it.

Documentation needs to be carefully cataloged because you’re keeping it for reference and if you need it, finding it quickly will be the most important thing.

Family memories should be shared with whomever is interested. You can put together an annual album, a collection of photos to document an event, or a collection of photos of a specific person and give them to whomever is interested.

In any case, choosing the useful/best photos is critical. Trying to do something with every shot you take will drive you mad.