My instructor (at the time the training director of the NSS-CDS) did the first day in the basin at Ginnie, first you demonstrated trim, propulsion, and ends the day with a five circuit drill that you have to pass.
He lays a line down, with placements, tie offs, and formations that require you to switch over the side of the line. The line is mostly in OW, but it deeps briefly into the ballroom entrance and back out. Then you do it eyes open alone, touch contact following, touch contact leading, eyes closed touch contact following, eyes closed touch contact leading, and finally alone with your mask off.
After day one assuming you had no issues everything was in the cave, in the cave zone.