Find a bouldering wall. Get a hold of some climbing shoes. Watch videos 5, 6, 7 of Climbing for Beginners [0].
Don't spend a lot on shoes, you will wreck them really quickly and you will certainly buy the wrong sizing when you start.
Boulder a bit and have fun. I enjoy bouldering with a friend the most as it really challenges me. Bouldering walls are often full of really cool and helpful people.
If you like it then watch some more videos to improve technique, think about what you are doing and practice. Consider trying rope climbing (you will want to take a short intro course for this, the rope skills are important).
Then you will start watching super cool videos [1], find yourself at the wall waay too often, and be more interested in finding out somebodies beta than their name.
