This article explains how to add a task to Google Calendar in the web, Android, and iOS versions of Google Tasks, Gmail, and Google Calendar, and how to manage task lists.
How to: Create a task in Google Calendar
When you’re working on your desktop, you can easily access Google Tasks from Google Calendar. Create to-do lists and add new tasks as needed.
Open Google Calendar, preferably using the Chrome browser, and sign in if prompted.
Click the Tasks icon in the right panel.