What you have is a Prindle 16 tramp, but it sounds like the previous owner of the boat had used a different tramp. The new tramp should slide in both the front and rear crossbeams. Then you can use the lacing and go through the two rows of grometts to tighten. There should not be any rear cross bar sliding loops. The way you describe what you have sounds like how a nacra tramp would lace not a Prindle
You can download a Prindle manual from performancecats.com