1. The first step is to open Google Calendar. 

Step 1 image

2. Right Click the three lines

Step 2 image

3. Click Create QR Code for this page. If you do not see this option, you will first need to download a QR Code Generator

Step 3 image

4. Click Download or copy and paste the link. 

Step 4 image

5. That's it. You're done.

Step 5 image

Interactive tutorial