Making a countertop is really very easy. Most countertops are built with flake or particleboard. No OSB.

You would cut the top the size you need and then build up the edges with the same wood but only 2-3″ wide. Each one is 3/4″ thick making the total thickness 1 1/2″ wide. Also making sure that you add cross pieces, from front to back, and placing them where the cabinets come together. This will ensure the top won’t sag.
The laminate. Your top is 1 1/2″ wide. So you’ll want to cut these laminate strips at least 2″ wide. Ensuring you will have the edge completely covered. After you trim the edges you’re ready to do the same for the top.

The top is not as easy as those little skinny edges. Only because the piece is much bigger. After you place the glue on the top (wood) and laminate place wooden dowels about every six inches, yes right on top of the DRY glue. Place the laminate right over the dowels. Once you have the laminate square with plenty of overhang on all sides start removing the dowels one at a time pushing the laminate down towards the next dowel and so on. Making sure not to leave any humps or air behind. Once the laminate and top are in contact with each other, that’s it. You bought the farm. There is no way in hell you will be to pull it back apart. I mean if you let the glue set upright.