Shows a summary view. Each day is coloured depending on what records there are on it, to a maximum of 5 flashes per day. Selecting a day shows the records for it, in this case for the 28th December 2019.
In this view you can see detail for a particular track and 'paint' days on the calendar to record things. In this case, I've selected the track 'Bike Ride' so I can see and edit the number of bike rides I've done in December.
The calendar scrolls as normal so you can explore and edit other months. By painting days into the future, you can use BuJo as a planner too. Here for example you can see I'm planning to ride my bike on January 3rd, 4th and 8th.
Rotating your device from the main calendar generates this bullet journal view showing all track data for the current month. This view can become really pretty and colourful depending on how many tracks you have on each day, and the combination of colours you choose for them!