You most likely need a shop manual. The dash has to come out on parts of it.
On the passenger side take off glove compartment and all surroundings.
Disconnect the battery! For the drivers side take all parts and surroundings
I have done this 3 years ago so it is hard to explain. On the drivers side there will be the electric connections to be unhooked.
They have a lever that you just swing down and move out of the way.
Like I said it is hard for me to explain. Shop manual has the step by step instructions .
You could do it without though.
Yes the top of the tower nuts are inside the van. Have fun.