It may sound counter intuitive, but it is best to first set up one zone on Flex Daily, the rest on Fixed similar to how your old controller was set up. Then for the Flex Daily scheduled zone, learn about and work through the Advanced Zone Settings (such as nozzle inches per hour, soil available water) — you can ask for advice here based on the plants and irrigation system you have, if you like. Once that zone is dialed in, and you see how the Soil Moisture chart and table work and respond to your settings, then perhaps switch another zone or two from Fixed to Flex. Fixed schedules have lots of intelligence features so you’re getting full value out of your controller!
Note that every time you change a Flex Daily advanced zone setting the moisture chart will reflect the changes immediately and you can see when it’ll water based on environmental conditions and your settings.