1. As Mom said, you need a kit.

2. It's not normal to lose your pump 2x in 5 years, unless it's lightning or thunderstorm related voltage surges. Which Hayward pump?

3. Sand does not normally need to be changed. BUT, if your pump is too big for the filter, you may have lost sand with each backwash, and my need to ADD sand. Insufficient sand will lead to a persistently cloudy pool. Which filter?