You so want a walking foot! Where possible purchase the one that "goes" with your machine. It is amazing the difference between the manufacturer's walking foot and a generic one. Just how it lines up with the machine's feed dogs makes a big difference. I had to replace my Bernina Walking Foot after 12 years of use. Couldn't imagine that I could have worn it out, but I did, 1400 Charity Quilts later!
Some versions may be difficult to attach. Try removing your Needle Screw (this also removes the Needle). Place the claw arm over the area where the Needle Screw goes, replace the Needle Screw and your Needle and tighten in place. See if that works.