The Focus Mode is a feature you can use to work on a particular task.
It hides the task list and the calendar, eliminates all distractions and helps you tackle a task at a time.
Click on a task and hit 
F to open the Focus Mode and ESC to exit it. 🔖 Its autosave feature will make sure that you don’t lose any of your work.
ℹ️ You can click on the i icon to check the task’s information.
🗓 Hover on the right side of the page to check your calendar.
👀 Look at the bottom of the page to keep an eye on your next task or event”
Need to focus on a time slot and its tasks?
Hit the shortcut F to “Pin” your slot and open a new column for a wider view of your work.
Read more here 
Time Slots