Lube the chain about once a week, more if it rains.
Pump the tyres up every few weeks.
The friction d/t gearings needs very little maintenace, a drop of oil once/month.
Rinse the bike if it starts to get too dirty, every few weeks.
2-monthly, swap the chain for one that has been sitting in solvent.
6-monthly, repack wheel bearings
Annual service and clean/wax