Spoiler You can finish by positioning B on the mid-level platform just over the target. Then release the zapper, and zapped B falls on the finish cube Was that your intention?
Spoiler: Another way Another way to win is to use the free-draggable. That is the second reason why free-draggables are bad. The main reason being that they are hard to manage as a player. I'm not even sure why it is in this level. Say, given the feedback, you may want to go back and make some adjustments. If that is the case, it would also be a good idea to put a title and author on the card. It's super easy to do from the Level Editor just by tapping on the defaults when the card is displayed. There is a handy guide on sharing a level including labeling and setting up an album here. Whether you re-post or not, you can create your own album and move this card there. If you are going to re-post, best to delete this version of the card from the forum using the delete feature above the card image. Thanks and welcome to the forum!