Depending on the kit, I usually leave the idler and drive sprocket unglued, so they can turn…I’ll assemble the tracks (I’ve only used Model Kasten) and literally thread the tracks on the same way you would on the 1:1 vehicle. Once I’m happy with the positioning, I’ll put a drop of CA (with a long glue tip) on the inside of the drive sprocket and idler to keep them in place.
Jeff