It shouldn't really be that different from any other beach cat except that you probably have a third cross beam at the bows.

You basically have three wires that hold up the mast; one forestay and two sidestays (sometimes referred to as shrouds). You may be able to identify which is which because the forestay is probably a different length than the two sidestays. The sidestays should be the same length. All three wires should come together at a tang located at the top 3rd of the mast and will likely be attached together to this tang with a large shackle. On the boat, the sidestays attach to the chainplates that come out at the outer side of each hull and should have some sort of adjustment plate that has 8 or so holes in it in which to pin the shrouds too - to begin put the shrouds in the upper most holes and adjust later. Attach the foot of the mast to the rotator ball on the middle beam and step the mast. Once the mast is stepped up, the forestay will attach to a similar fitting located at the center of the front beam. Now, equally adjust the sidestays down (while someone holds the mast to that side by pulling on a trapeze line) until the rig is snug. You may find that you have to move the forestay in it's adjuster until you find a happy medium. Once this is set, mark the holes for everything so you can come right back to them next time.

Does that help?