CLimbing up the ladder is just a matter of facing it square on, looking up a little and using the forward button.
There is no really good way to go down the ladders in this game (unfortunately) the most common method is fall and splat.
The "Use/Give" window has two options - make sure that you have choosen the GIVE option and use the arrows above and below the window to scroll through your items until you find the potion (or whatever you might want to give). The toad is not easy to catch
Try to corner him against some trees if possible and have the person with the potion already to "give" so you don't need a lot of time to set that up.
Look for a lever on the wall in that big room in the crypt. Flip it and the dungeon will load.
Lots of folks have had these difficulties! You are in VERY good company!
Wyv