Your all-in-one impassa system is the main "keypad". Did you have other wireless keypads in other locations? You may be able to reuse them, but I prefer hard wired keypads.
The basic panel is a circuit board, generally it will come with a metal cabinet. A transformer, battery, and wired keypad are required. You often see bundles that include all of the above. To use wireless sensors a wireless receiver is required this can be installed in the panel or is built into some keypads.
I'd expect you to find the installation process difficult. I think you've got a steep learning curve ahead. How many sensors do you have currently?
I don't install alarms regularly, meddling with them is just a hobby. For DSC panels their DLS5 software is by far the nicest way to program them. Forget about your ADT Pulse garbage and sell what you can on ebay.
I have 1 wireless keypad. 1 dsc impassa key pad. 3 door sensors , 4 window sensors. 3 smokes. 1 co sensor. My adt pulse net gear hub is dead. I went to Home Depot and I noticed they make a wink hub, Can I use this hub and connect directly with my keypad and sensors by programming it on the phone app? I'm going to remove the cameras totally and do a separate system. If the wink hub wouldn't work is there something similar? I would really just like to use the wireless devices since they are new.