Don't glue it LOL ... I tried that on my first one ... it doesn't work (thankfully, I was just practising and didn't wreck a quilt!)
I put the batting on the floor and then iron it. Then I put the backing on and iron in and then I tape it to the floor. Then I put the top on and iron it.
I always iron from the middle out - but you are pressing ... not ironing to the point of warping the fabric ... make sense?
The I pin all the way around the edges. Then I sew it together and turn it inside right.
Try a small one and you'll see how it works!
Good luck!