The length of your cycles is one of the building blocks for inne's algorithm to predict your fertile window and ovulation. That's why it is important to track your period and create a new cycle in your inne App once your menstruation starts.
You can do so by tapping 'track your fluids' and choosing 'period'- a pop-up will ask you to confirm the date and automatically start a new cycle for you. To help you remember it, the inne App will also notify you when it's about time :)
If you realise that you forgot to track your period, simply swipe the progesterone graph to go back in time and select the first day of your latest cycle, log 'period' and confirm the date - that's it!
Alternatively, you can go to 'your cycles' from the inne App's settings and tap 'Edit Period Dates' to adjust your cycle dates.
Please note that 'spotting' is not considered period bleeding. If you log 'spotting', inne won't start a new cycle, but assume that you have light, inter-menstrual bleeding in your current cycle.