Thanks, but like I said, I'm just too inexperienced at riding public transit to trust myself solo on them right now.
You should practice. When I first moved here I was confused too but it was so simple after I learned how to look at the BART map... which is the most straightforward thing I have ever seen now that I've used the trains for so long.
Now muni is another matter. The trains are easy enough, the bus routes look like a tangled web so you have to practice more on those.
I'd recommend just picking a destination you haven't been to before and want to visit, and make an effort to BART/Muni there as an experiment. You'll get the hang of it.
Having a smartphone helps. There are tons of apps for this kind of thing. Google Maps is by far the most versatile though. Apple maps doesn't have public transit info :/ For BART/Muni arrival times I use Routsey Pro. Google maps has arrival times but it's a bit of a convoluted process if you have lots of routes you regularly use. Dedicated apps let you bookmark your stops, etc.
If you SERIOUSLY get lost, most bus stops have maps on them or nearby.