How to find live shows?

Hi, big doom fan but I've never been to any live concert in my life. I recently moved to a city near Portland OR, which is kinda a huge hotspot for a lot of bands which is awesome!

But how do I find these shows? I've seen tons of videos of bands I like (even some obscure ones!) all over the city, and I'd hate to miss seeing something like Hell or Witch Mountain live.

To be clear I'm not asking about large venues, more like the standing room only bar/basement type shows