It is, of course, best to work with and learn from an experienced and well trained yoga teacher. Just as you would not go on to a football forum and ask how to tackle, then expect an invitation to the Football Combine preceding the NFL Draft, neither should one expect to “learn” too much of this from the internet. So please consider finding a teacher in your area. If money is an issue then try bartering or volunteering at a studio. If you need some direction for that, please ask.
That having been said, for linemen I think there are three critical movements or groups I would be focusing on. The first is backbends. The second would be the six movements of the hips (flexion, extension, internal rotation, external rotation, adduction, and abduction). And the third would be the release of tension in the neck, shoulders, and upper back (trapezius, levator scapula, serratus anterior).