I promised you the fastest way, so I wont waste your time.
Just follow along the Steps
Step 1. Get your current TimeZone
Step 2: Get the value for the timzezone you want
Now select the timezone, by passing the numbers corresponding to the value you want to select
Step 3: You will get a result similar to this
Step 4: Use the TZ value you received in the previous step and run the below command on your terminal
timedatectl set-timezone Asia/Kolkata
Step 5 : Verify
Run the date command again to verify
That’s it! Cheers! See you in the next one.