I,m stuck on the part where you are supposed to use Sobek's staff on the crocodile. I use it on him but nothing happens. Is there a certain spot I,m supposed to use it on him?

Be sure that you know how to use the crocodile from the old man.
Then be sure that you have the rope tied to the neck of the crocodile.
Also double check that you have the rope tied to the short end-close to the wall part of the rod inserted in the column.