I have my charracter, go into AI Packages, click 'new' and click on sandbox package in cell whatever. everything else is default. The people dont even move. What is going on?

Sounds like you forgot to http://geck.gamesas.com/index.php/gamesas_Tutorial_Navmesh your cell. Without a navmesh NPC's don't know where they can and cant walk, thus they usually stand still and dont move.

I should have thought of that. thanks. And are Idle markers those blue people-shaped things?

For the most part, yes. They are technically called furniture markers. But alot of them are, if you place some and an NPC is 'sandboxing' within range, they will randomly interact with it. Things like the wall lean smoking marker, and pushups marker. So yea. But also those blue squares with an I on them, and an arrow on one side. Those can be used as well, and often are a combination of many idle animations they can randomly perform at them.