How do I prep a laminate or Formica counter before pouring epoxy?

Very little. Laminate and Formica don't need sanding, a bonding primer, or an epoxy seal coat. UltraClear Bar & Table Top Epoxy is a stand-alone product, and laminate is non-porous, so you go straight to the flood coat.

The only prep that matters is cleaning. The surface must be completely free of dirt, debris, residue and oils, and completely dry. Then pour the flood coat directly over the counter and let it self-level to 1/8" thick. The tutorial videos show how the flood coat goes on: https://www.bestbartopepoxy.com/tutorial-videos/

If the laminate has been painted, latex and water-based paints are best; the epoxy can go over them after about 24 hours. Oil-based paint takes a long time to fully dry, so seal it with 3 coats of oil-based polyurethane first or the epoxy may not bond properly and can delaminate later. The same goes for any other incompatible finish, such as oil-based stain.

If part of the counter already has an old epoxy finish, scuff-sand it with 220-320 grit sandpaper, wipe it with a lint-free rag and denatured alcohol or acetone, and let it dry before pouring. The flood coat fills the sanding scratches and cures clear.

Where the counter meets a sink or stove, you can pour right up to any edge that sits 1/8" or higher above the surface; the epoxy won't flow over it. If the edge is level with the counter, build a temporary dam from wood covered in epoxy tape.

Full instructions: https://cdn.shopify.com/s/files/1/0320/7168/0140/files/Epoxy-Instructions.pdf?v=1616443869