I started climbing in graduate school, mostly in climbing gyms. Outdoor climbing is much more physically intense and time consuming (days versus hours for indoor climbing), both of which I dislike.
There are essentially two types of climbing: with and without rope.
- with rope
- top roping
- without rope
In top roping, you are attached to a rope from above so that when you fall, you don’t fall too far. In leading, the rope is beneath you and you need to clip it on to the pre-set carabiners on the wall (or rock) as you climb. Thus if you fall, you fall twice the distance between where you are and the last carabiner. In general, leading is harder than top roping because one hand need to be free to do the clipping. Indoor climbing gyms provide all three types of climbings. You will need to go through some simple safety training for top-roping and some serious body conditioning for leading.
I don’t like being tied to a rope thus I almost only do bouldering. Since there is no rope, bouldering problems are only 3-5 meters high, which could still cause serious health hazard. Bad landing/falling could result in COMPLETELY broken ankles. Thus it is wise to use caution and avoid bold moves.
I find bouldering much more fun than top roping. Usually, the routes are designed to test specific climbing techniques. In other words, there is A solution conceived by the setter. On the other hand, you can improvise and solve problems in your way.
The climbing route is usually taped with a single color and only the taped holds can be used. Indoor gyms update the routes once a month or so to make people engaged. The grades are logarithmic, i.e., each grade is a big skill bump from the previous one. At my best time (late 2014), I was able to do all V5 I encountered and some V6.
The best climbing book I have read is the self coached climber. Its techniques work!