2 - 4 hours
I was replacing the front panel of my dad's iPad after he dropped and cracked it and in the process ripped the original antenna due to general carelessness and a lack of planning
The new antenna itself went in smooth as silk. Getting the front panel off is not something I particularly want to do again, but swapping out the antenna was just a case of "screw this in here, here, here, and here and pop this attachment onto the logic board." Then once I verified it worked I went back and undid it so I could sticky it in place and repeated the connection process
Once you get the front panel off the antenna goes in really easily. Getting the front panel off is much easier when you use a small screwdriver that's been filed on one side to make a small chisel. A metal screwdriver is much stronger than the plastic opening tools and won't bend.