Briefly, zones represent physical valves which are all independent of each other. Sequences allow you to group the zones and run them in a particular order. Schedules can be attached to either zones which means they will each march to their own tune - possibly even overlap (multiple valves open) or attached to a sequence where you instruct the commencement as a series.
Just one thing. YAML is very picky about indentation and it means a lot. If you share your configuration please put it in fenced code blocks. This will stop the text being squished to the left hand margin and help a lot with support. For example.
```yaml
irrigation_unlimited:
controllers:
- name: 'My Garden'
all_zones_config:
show:
timeline: true
zones:
- entity_id: 'switch.my_switch'
schedules:
- time: '06:00'
duration: '00:20'
```
Hopefully I have not confused you further.