We called to make our booking (the number is on their website). They sent us an email confirmation after the transaction. FYI, our guide told us that she once lead a 95-year old man on the course. If your 75-year old person can “climb stairs,” you should be fine. There is a wood/rope bridge that you climb that is roughly the equivalent of 3-4 flights of stairs, and a steep “stairs” trail to climb. Otherwise, it’s all “downhill” on the zip lines. This is a first-class operation and we had a great time with them. Do it!