SNAKE IN THE BASEMENT

iS THAT A SNAKE? I asked myself when I went down to the basement to check on my laundry. Don't panic. STAY CALM. FIRST--FIND OUT IF IT IS POISONOUS, I said to myself. Naturally, I ran upstairs to get my camera phone, but the snake had disappeared by the time I returned.
Fear ran through my body. WHO SHOULD I CALL? I had no idea.  SHOULD I BE SCARED? I had no idea. WHAT KIND OF SNAKE WAS IT? I had no idea.
Thank God for Google. I found out that my guest was most likely a garter snake and garter snakes are not poisonous. Relief. But still, not my idea of a pet. NOW WHAT?
Actions to take: 1. Place a towel under the door at the top of the basement stairs to keep visitor in the basement. This is not just for my safety but the safety of my cat. A snake bite to a cat, even from the "harmless" garter snake isn't good.
2. CATCH AND RELEASE. But how?
3. PATCH UP THE TINY HOLE IT SLITHERED THROUGH. But how?
4. DECLUTTER THE BASEMENT BECAUSE IT'S A MESS AND I SHOULD.  I know how, just don't want to. Well, part of me does. Now I'm motivated. At least a little.