Several pieces make up the faucet fixture:

the faucet (same shape as the door handles)

two knobs (one red, one blue)

three bolts (one for each knob and the faucet)

five nuts (two for each knob and one for the faucet)

a base plate (small rectangular piece of plywood)

Start by marking the center of one end of the faucet and drilling a hole straight through it, big enough for the bolt to pass through. Each of the knobs already has a hole through it because of the way they were made.

The bolts have to pass through the knobs/faucet, through the base plate, and through the plywood counter-top. That's 1.5" for the knobs, but about 2.5" for the faucet. It turned out the bolts I had weren't long enough to go all the way through the faucet, the base plate, and the counter-top. So I improvised by sinking a nut into the bottom of the base plate. The faucet bolt threads through that nut.

(A simpler solution might be to find a longer bolt, but this was actually easier for me, and you'll know what I'm talking about if you've ever tried to go shopping for hardware in Brazzaville. There are a thousand micro hardware stores, none of which have what you want. But I digress.)

I measured symmetrical locations for the holes in the base plate, and then used the base plate holes as a guide to drill the holes in the counter-top behind the sink.

Put a bolt through the faucet. Screw the faucet bolt down into the hidden nut.

Put the bolts through each knob and then screw a nut on all the way up the bolt till it touches the knob. This will be a spacer between the knob and the base plate. Pass the knob bolts down through the base plate and then down through the counter-top. Screw a second nut onto each knob bolt from underneath the counter-top. This will hold the base plate and the whole faucet fixture onto the counter-top.

Once all that is fastened the faucet fixture is finished.