It's a double pole 5 position switch. Each bank has 5 positions and they are labelled SW1-A and SW1-B - which is interpreted as
Switch 1, bank A and
Switch 1, bank B. Each bank is electrically isolated from each other, but are operated together through a common mechanical movement.
You can have it in a linear arrangement or rotary. Rotary is the most common in my experience.
There are many ways to build a rotary switch - so I'm not going to try to describe more than just this one style....
A common style is a single wafer with 12 contacts spaced at 30º around the perimeter. Inside this ring, there are (typically) 1, 2, 3 or 4 other contacts. All these are fixed in relation to the body of the switch. Mounted to the shaft is a switching plate that will have 1, 2, 3 or 4 pairs of wipers.
You can get them with PCB pin or eyelet terminations:

The configurations possible are, respectively, 1 pole, 12 position; 2 pole, 6 position; 3 pole, 4 position and 4 pole, 3 position. This is the general construction - you buy your switch in one of those configurations.

There is usually a mechanical stop at each end of the rotation movement so you know when you've reached the first and the last position - but you can also buy a switch that has these mechanical stops placed differently. This means what looks like a 2 pole 6 position switch can have a stop after the 5th position - so it pays to check how many positions a switch actually has before soldering it in.
Edit: Spelling