"Jacob had a dream"
set up on the earth
"with the bottom of it touching the ground"
reached to heaven
This refers to the place where God lives.
The word "behold" here alerts us to pay attention to the surprising information that follows.
Yahweh stood above it
Possible meanings are 1) "Yahweh was standing at the top of the stairway" or 2) "Yahweh was standing next to Jacob"
Abraham your father
Here "father" means "ancestor." AT: "Abraham your ancestor" or "Abraham your forefather"