This structure may change depending on the team, but things that should be covered in each monthly session on Zoom are:
General check-in with the team member on how they're doing. This could be anything including personal life/workload/work-life balance etc.
Ask the team member if they need support with anything in particular/anything they'd like to mention or raise/any issues or concerns?
Check-in on their delegated hours, how this is going, do they need any support?
Mention anything you need to raise as their team leader for them to improve/work on.
Review status of any action points or goals set last month.
Set some new short-term goals (things to work on before next 1:1) and some long-term goals (6-12 monthly goals) with the team member, or check in on those long term goals if already set.