First, welcome to the board I am sure others with far more expertise will be able to help, but as suggested a photo of the block is always most helpful.
90.00 for her ruler? I hope it also came with a book and other rulers, if not I say you got taken, and while I’m all for supporting local shops, I think if you paid 90.00 for just the ruler, ouch! Even on her own site, her rulers are not that expensive!
Deb Tucker’s rulers are all about oversizing and cutting down, so if something is not lining up then there is a issue.
Say you want to make a 8 inch finished block (a finished block size is the size of the block once it’s sewn into the quilt). You will then look at Part A (left side of ruler)on your ruler and cut a square that is 5.25 inches, and then cut that once on the diagonal. Then you will find your finished size on the ruler and it will tell you what size strip to cut for your center square.
If your wanting to make a snails trail block, then I’m not sure that this ruler is designed for multiple rounds that is needed. There is a creative grids ruler (certainly not 90.00) that is also a square in square and allows for multiple rounds as needed for the snails trail block. We have lots of math gurus on this board, and so I’m sure if you posted your desired finished size, someone will be able to give you much better directions than I.
https://www.amazon.com/Creative-Grid...70_&dpSrc=srch