When starting a project in garment sewing and sometimes with a quilt project, I was taught to find the true "grains" by lining up your selvage, smoothing out your fabric. If it is wonky, have someone grab one end of the panel to see what corners need to be pulled. Then have the other person grab that corner of the panel, you grab the diagonal corner and pull.,this will stretch the panel, so the sides line up.,if it it doesn't,,stretch it again. This works when the fabric has been tightly wound crooked on the bolt. If the panel is printed crooked on the fabric you cannot fix a misprint. Best wishes for a good outcome.