I’m not exactly sure if you’re confused about multithreading or odometry itself, so I’ll explain both.
Multithreading allows you to run 2 loops at the same time. You can learn more about it here: How to use VEX Threads
On the other hand, odometry is purely position tracking. In other words, all it does is track the position of the chassis. For the chassis to actually move, you can use something like PID. For example, if you wanted to move to the position (5_in, 4_in), you can use trig to figure out the angle you need to turn to, and the distance you need to travel to reach the point.