based strictly on handmade quilts I’ve had in the past
A quilt is a “sandwich” made of
the top layer – the squares or odd pieces that you sew all together
the bottom layer – usually just a plain complimentary fabric
the middle layer – the batting, this is the “insulation” to make the quilt warm and fluffy.
You tie knots or sew a pattern through all the layers to keep the batting from shifting around and making lumps.
sorry, can’t help with actually making one. If you’re just using squares all one size, you should be able to just sew them all the same, giving yourself a uniform seam allowance so that it ends up aligned correctly. I’d probably sew squares into long strips, then sew the strips together. Keep in mind I haven’t done any sewing in years, and never made a quilt 😉