It really is quite a quick process once you've developed the knack of hand planing. But I'd get a couple of scrap boards and practice on those first.
My technique, about 50 ukes in to building is to clamp the board down with two clamps and plane at 45% to the grain in three stages:
1. A clamp at the LH corner and about 1/3 way from that corner, and plane the RH side of the board.
2. A clamp at both LH and RH corners, plane the middle.
3. A clamp at the RH corner and one about 1/3 way from that corner, plane the LH side.
For the next pass I rotate the board 180 degrees so I'm planing in the opposite direction.
I use three planes for a soprano board: a smoother set to take a thick shaving, which has a steep camber on the blade; a smoother set for a fine shaving which has very little camber; and a block plane. As I get closer to final thickness I switch from the thick shaving to the thin shaving smoother, then finish off with the block plane. But you don't need the block plane, I just find it handy to creep up in the final thickness taking small shavings.
Rather than try to plane along the grain direction, which risks the plate buckling as you push the plane, I finish off with a hand held cabinet scraper.