I did this over the weekend. My wife found the slide at a yard sale, it is a playground slide. I attached it to our old pool ladder. I cut the sides of the slide back enough so it would hang over the top step on the ladder, then attached it to the ladder with stainless carriage bolts. I put stainless screws through the ladder legs into the bottom step on each leg, then screwed the ladder to the deck through the bottom step. It is surprisingly solid.
