Need help with EVA, command chips and assigning astronauts

I had been away from SR2/Juno for several months. I started back playing in March. During my absence from the game, I've forgotten how to do 3 things.
1) How do I activate the tether when I have an astronaut in EVA?

2) How do I switch between command chips, in different parts of a rocket/spacecraft? I've forgotten the key that does that in flight.

3) How do I assign an astronaut to a command capsule? I put the astronaut in the capsule but I see "Unassigned" next to the astronaut's name.