It's simple. Load your figure, then go to File menu and select import BVH. then select the bvh. then a message appears to orient it....i choose along X axis it works fine for me. then another message and i choose Auto Scale. Then a message appears saying that no corresponding Chest or something was found...it's ok, the bvh was made for other kind of character that have different body parts that's why the message pops up.. but still it works on poser human characters. just ignore the message. Then the figure goes above or below the ground plane..but just a bit, unlike other bvh files. you can change ytrans for Hip but make sure you turn of IK before doing so.