Welcome! I read this post with tears in my eyes. I love how you immediately stepped in to care for your beardie in more ways than one. You are definitely in the right place and there are so many of us here to help. There are others you are helping as well, trust me.
Welcome to the family- Pogo is beautiful!
It can go on top (your screen looked like wide hole in the pics). 12 to 15 inches from Pogo. If it's on top i would try to get closer to 12 inches than 15. If you can get your ubv light and basking light to over lap a little, that is the idea situation for the lights.
So totally confused now. I've got the T5. Its 24" so i can place it on the long side of my tank...correct? Do I still need the heat lamp? And which should go over the basking area?
The t5 is the uvb, the basking is for heat. You should have some kind of decor that Pogo can climb up on, place the basking directly over that decore. Pogo should like between 95 and 100 degrees temp in the basking. Try to situate the uvb so that it is on him in the basking area also. The uvb is needed so they produce vitamin d3 naturally, d3 is needed by their body to absorb calcium. It prevents metabolic bone disease. The basking is for food digestion, they can't process food correctly if they can't get up to temp. If you don't have room to make the light from each bulb overlap, you can setup 2 areas with decor and pogo should move between the two as needed. It's just less work for them if the light overlaps because they can get heat and uvb in one place. If you set up two different pieces of decor, make sure the distance between the top of the decor and the uvb is less than 15 inches.
This is what I’ve done. The new t5 is sitting right next to the other lamp, both pretty much over the basking area at 11-12 inches, depending on what rock he chooses. Comments welcome