For the teleporter stones, you need to click and drag one out of your inventory (or off the ground), move it where you want it to land, and release the mouse button somewhere there is no red x. I tried this in DD to get up onto the mountains in the Dark Forest, and had to play a bit to find a spot to stand where I could get the teleporter stone onto the mountain. For the toss onto the mountain and when moving around there, I had to vary both the direction I was trying to toss and the distance, to find an area I could drop a teleporter stone. In BD it is more difficult to toss a teleporter stone outside the play area, because the graphic of the teleporter stone quickly becomes blacked out.
Try using the method in the armory trick in act 1
topic to get a summoning doll through the wall. In the main game, you can then have the doll enter the BF and when you return, both your main characters will be past the wall, but things are a bit more elaborate in the BF. First, give the summoning doll a container (drag and drop it onto its portrait) and have him drop it on the ground, and then open it. Open your main character's inventory and drag and drop a teleporter stone into the container's inventory window. Next, have the summoning doll drag and drop the teleporter stone onto the ground. If you have another wall to get past, drag and drop the packages (or crates, etc) you used for the armory trick into the container inventory, so you can use them again). Finally, use the other teleporter stone in your inventory to bring both main characters through the wall. You can drop and use the teleporter stone if you want to get back that way, assuming you only have one wall to get through. If there is a gap between sections so you need to do this twice, you can keep both teleporter stones with you, finish the dungeon and simply exit the BF to get out.