1. Get your Pi ready

• You should start with a WiFi enabled Raspberry Pi connected to mouse, keyboard and monitor, you can learn here how to do it using an Okdo Pi kit

2. Update using Terminal

• Open Terminal from the Pi’s menu bar, it’s the folder-looking icon
• Type the command shown below in the Terminal window after the $ and press Return

sudo apt-get update

• Wait for Terminal to finish its process, list all the packages that need to be updated

If you get the following message:

E: Repository 'http://raspbian.raspberrypi.org/raspbian buster InRelease' changed its 'Suite' value from 'testing' to 'stable'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.

Type the command shown below in the Terminal window and press Return. Skip this step if you don’t get the message

sudo apt-get update --allow-releaseinfo-change

• Type the command shown below on the Terminal window after the $ and press Return

sudo apt-get upgrade

• After Terminal runs its process, you will be asked if you want to continue. Type Y (for yes) and press Return
• Terminal will run its process which can take a little while as it will download the necessary updates. When it finishes it will display the $ sign. You can then close Terminal and reboot your Pi