Examining a scarf joint. To glue the pieces make certain that the plywood rests on a nicely flat, non-stick surface with the GOOD SIDE UP.

Bring the sheets close together and align them so that you don't need to do much manipulation after the glue is applied. I also assume that you did some experimentation prior to scarfing to see how the plywood grain and color would match across the panels and which ends would end up together! I highly recommend to number them so that you don't need to Waltz around your shop with 8 foot sheets already adorned with fragile, razor sharp scarfs.

As usual, mask whatever you don't want to waste your time on cleaning. The tape edge is even with the scarf edge.

Speaking of pressure, it should be distributed evenly along the joint.

Whole 24 feet. The Cirrus hull plates were made using only these three 2' x 8' sheets. This is also true of the deck if you are going to make it only from one type of plywood.
If your shop is not that long, you can make shorter sections (18 - 19ft) which do reduce the economy of the plate layout and will require one additional 4mm x 4' x 8' sheet for the hull. See S&G Manual for layout options.

Alternative (bad) example of a scarfing clamp as well as the 'scarf gluing' clamp. In this instance, either the plywood cannot be clamped sufficiently, or the pressure on the ends bows it out in the middle.

Solution. Doubling scrap pieces with a spacer. The pressure is more even with this three pronged approach.