At the moment, you cannot set reminders for live TV directly through the main Freely TV Guide.
Reminder Availability
While the core Freely platform doesn't have a built-in reminder function, many of the individual player apps (like BBC iPlayer or ITVX) may have their own features that support reminders for their specific content.
What to do:
If you need a reminder, check the respective player app's website or settings to see if they offer an alert system. Freely will let you know if this feature changes in the future!