Mine are grown up now - but what helped was:
Routine. Breakfast at the same time every morning, at the table. Not negotiable. We all sat together.
Then outside. Anything outside, regardless of the weather. Some 'outside' had a focus (i.e. getting to toddler group etc - again, they knew the routine of what happened on which day). Other 'outside' was to the shops/to play/poke around with sticks in puddles. Outside included a snack and drink.
Lunch. At the table. Not negotiable. If we were out with friends, then obviously a sandwich or whatever. But sitting together was not negotiable. No getting up and running around and smearing food around etc.
Quiet time - stories and sometimes a video (we didn't have a TV and this was pre-phones/ipads etc).
Filling in the time somehow until tea, bath, stories, teeth, bed (again, not negotiable). This could feel very long.
Toys with small bits were played with sitting at the table so younger ones couldn't swallow said bits.
It sounds very boring when written like that, but everyone knew where they were and everyone was ok with it. The one thing I never did was tidy up - the house was a complete tip. But it still is now, so I can't blame the DC.
I was largely doing it alone as husband was mostly at work.