Use a 5mm hex and hold the blocks with a large wrench of some kind.
DO NOT screw this up! The bearing protection is marked left or right.
Right: the side with the valve stem.
Left: the side with the cable.
Clean everything thoroughly with isopropyl alcohol and then apply grease as shown from the syringe. Careful, the syringe can jam and then shoot grease everywhere. Use about 1/4 of the syringe per side, saving the rest for when you need a top-off down the road. Check your grease levels every 500 miles or so.
Keep the assembly together during install. If the seal pops out, take everything back, re-assemble, and start over.
And make sure the grease seal assembly is pushed down all the way around.