Step 2: How to use Cydia: Upgrade Cydia
From here if you haven't run Cydia in a while, or this is your first time running, you may get a notice about "Essential upgrades". These are upgrades to the Cydia application itself that may be required for installing new packages and apps:
* Press Upgrade Essential
* Press Confirm to begin the download and install
* Wait for Complete and press Close Window
* Press the home key, and then re-open Cydia to continue
NOTE: After installing essential upgrades, it's always a good idea to restart Cydia to make sure the new packages are reloaded. Repeat Step 1 to open Cydia again (though you probably already guessed that).