Mornings usually start early, before the heat builds, with a guided excursion to that day's temple or site — a licensed Egyptologist guide leads the group on-site rather than leaving you to read a plaque. See What Does a Nile Cruise Egyptologist Guide Actually Do? for what that role actually covers.
The sailing afternoon
Afternoons are often spent sailing to the next stop, which is genuinely one of the appeals of the cruise format — time to relax on the sun deck, read, or watch the riverbank scenery of villages, palm groves, and farmland pass by while the ship covers ground you'd otherwise spend on a bus.
Evenings
Some days include a second, lighter excursion in the late afternoon or evening — a lit temple visit, a felucca sail, or similar (see What's a Felucca Ride and Should You Try One?). The ship usually offers something on board after dinner: a themed night, a folkloric show, or simply the lounge and bar. The overall rhythm balances real sightseeing with enough downtime that the trip doesn't feel rushed.