I can not figure out how to set a straight stitch. I don't want a zig zag or a decorative stitch. How do i set my machine to do this?

First, make sure you select the straight stitch setting on the round dial. It is the one that has the dashed lines, looking like the stitch itself. Then, you may also want to be sure that the stitch WIDTH (dial with the picture that looks like a straight line gradually turning into a zig-zag) to the lowest setting, which is generally 0. With some machines, even after selecting a straight stitch setting, moving the stitch width can change needle position. Sometimes it will initiate the zig zag, other times it will move needle position left to right. Does that fix it?