Apparently "Ambrose" is the last name of a Michigan couple who introduced a type of golf scramble to locals while living in Australia where it became popularized as the Ambrose golf format.
The Ambrose scramble format is fairly straightforward. Everyone on the team - usually 2, 3 or 4 players - tees off. The team then picks the best shot amongst their team players' shots and all play from that spot. Each team mate must place the ball within a hand's length of the chosen ball's lie. On the putts they must putt from the same spot. Each team records just one score per hole.
With Ambrose golf rules you use a team handicap. Generally the formula for the team handicap is as follows:
Team Handicap = Total of all team members' handicaps ÷ (Number of team members x 2)For example, on a 4-person team with handicaps of 5, 13, 18 and 25 you would calculate as follows:
Team Handicap = (5 + 13 + 18 + 25) ÷ (4 x 2) = 61 ÷ 8 = 7.625 or, Team Handicap = (5 + 13 + 18 + 25) x (100 ÷ (4 x 2))% = 61 x 12.5% = 7.625
The tournament committee can decide whether to round up 7.625 to 8, truncate to 7 or something in between.
Another twist that is sometimes added to the Ambrose golf format is a requirement that each team member's drive must be used at least a certain number of times. The tournament committee can select whether that is one, two, three, four or more times depending on the size of teams. That puts pressure on drives towards the end of the round, so you want to make sure, if you've got a beginner or high handicapper that you avoid pressure situations for their drives late in the round.