I used terry squares for the first year of my sons cloth bum days. Am guessing you're having a boy as you've referred to the baby as Bert lol. For boys, I found the best fold was to fold the terry in half and lay it flat with the open end away from you. Then pick up the top left corner of the top layer and carry it over to the right top corner and put it down, so it's an upside down triangle. Then turn the whole thing over carefully (to begin with) and to your left should be a rectangle and to the right just the right side of the triangle from underneath. Fold the rectangle in towards the middle three times, so there's the triangle at the back and then the rectangle folded into a pad on the front. Does that make sense? Then when you put it on the baby, once you've nippa'd the front, tuck the leg pieces in. You can fold the triangle corners over on themselves to begin with, I used 60cm x 60cm ones to begin with, with a few Motherease wraps. I had 24 terries, they were great <3 Dry overnight on the radiator, no fuss lol.
If that doesn't make sense, shout and I'll see if I can find the folding instructions I used