I’ve found setting a routine of when I eat very helpful. Started doing it because I had no appetite or interest in eating but knew I had to eat something. I still eat to a routine almost 4 years later. I’ve never set a timer not even to remind me to sip fluids. I just eat to the time on the clock. I can eat earlier or later than those set times or miss a meal/snack (conflicting appointments, commitments, travelling, not hungry, etc.) but I don’t eat additional snacks/meals between those times.
Honestly, I really only ate two ‘meals’ a day those first two weeks. Sipped those shakes & soups for ages as I diluted them for extra fluid & so they’d taste a little better (they didn’t). Started my breakfast shake at around 8am & my dinner soup around 5pm if I remember correctly. On purées I began three meals a day & I added a mid afternoon snack I think from solid foods to ensure I was better meeting goals. My surgeon & dietician were okay with this as I was slowly increasing my intake every week.