I use kerapoxy a lot.
From experience make a decision about the surface of the tile, if it's to rough or porous it may not be suitable for epoxy.
Get the right tools.
Epoxy grout floats are very stiff, the newer the better, as the corners are "sharper".
Get the epoxy pads, they're a woven pad thing, similar to a large scotch pad. Don't use imitations as the dye or fibres may come out when grouting.
Plenty of sponges.
Step 1. Make sure all joints are clean and ready for great. You don't want to be wasting time once epoxy has been mixed.
Step 2. Use warm water for washing. Again, get it ready before mixing epoxy. Not all jobs have warm/hot water on site, so getting it can take time.
Step 3. I buy 2kg kits. I prefer it over 5kg as I can comfortably use 2kg before the workability becomes hard. Mix full 2kg kit. Don't mix partial kits. Mix with mechanical mixer only. Don't try doing it by hand.
Step 4. Grout. Work the grout in to the joints. "Cut" the excess grout off the surface of the tile with the edges of the grout float. The less you leave on the tiles the easier it is to wash.
Step 5. Wash. Use the damp abrasive pad to break up the grout on the surface of the tile. Use a circular motion, with only light pressure. If you're washing a lot you may need to change pads as they will clog up.
Step 6. Wash tiles with clean warm water and sponge. I normally wash twice. You need to take off as much residue as possible.
Step 7. Check joints. Make sure all are right and perfect as the next day the grout will hard and very difficult to repair.
Step 8. Following day, if needed I'll use the kerapoxy cleaner to polish up any residue on the tile.