I'm making a sunbonnet Sue quilt and I want to try this. I'm quilting a grid pattern. How do I get the quilt pattern to line up? Will it work or should I put it together first and then quilt the usual way? My machine only does straight and zigzag stitches.

Welcome, TXyankee. Your name caught my eye, because one of my online names is Displaced Yankee and I am also in TX.

Not sure of what you mean by "put it together first". You make the quilt sandwich before quilting. You can use masking tape to mark your grids for quilting and then skip over the Sunbonnet Sue's when quilting.

you can mark your grid lines with a ruler and a Hera marker or a credit card. something smooth and thin.the indentations are where you will quilt. then no markings to remove later.

With a quilt as you go, you quilt every block first, then you sew together with shashing strips. I don't think it will show if you off a little if you are doing diagonal lines. Even with a straight stitch you can do free motion stitching on each block , then every block could be different. Just remember that it already needs to be in a sandwich before you start. Also you need an open toe foot or embroidery foot if your doing free motion. It has a spring on the shank that helps release the tension on the fabric so that you can move it around.

put it together first. THEN

when you mark your grid.....measure on both sides down the edge in inch or 2 inch increments. Then with a yard stock or other long straight edge, connect the dots from side to side.
I have found that when I try and put one line thru the middle and then try and mearure from that lign, they never some out exact and the lines start bowing before you get the ends. So dotting the side and use the dots to aligh each mark works best. Does this make any sense?

Now. if you are going a quilt as you go, you must mark each block exactly the same and make sure each lines up with the one beside it It can be done but takes care in marking and joining the blocks.

The cool thing about quilt as you go is that you can quilt a square at a time for those of us that do not have a long arm.
I am planning to make a queen size quilt, and this would be much too big to get it quilted in the normal way, with my little sewing machine so I am using the quilt as you go. If you want your grid lines to match up just measure and mark each block the same.
Good luck to you.