When I started FT I used to just sit on the beanbag indoors with tge rifle, unloaded, and just find what suited my body.
Remember you do not want to constrict the body as it would influence what the rifle does. Then by practising it for 20 minutes every other night your body starts to grt use to a 'normal'position. You just need to fine tube it when at the club for the ground conditions.
Ideally you want to have the rifle aimed at the target without any 'force' being used.