Insert the stick into the spare USB port and turn C64 on.  The first time you use a stick you will need to update the firmware.   Instructions at the bottom.

 

A memory stick will now be at the bottom of the menu page.  Select this and the game folders will open on screen.  They are stored alphabetically. When you open a game, often the first screen to open will be the "crack" screen.  Usually the way past this is to open the Virtual Keyboard and press space or run/stop.

 

With the Mini/Maxi there are two types of joystick configuration which differs depending on the game. To change the joystick port hold down the menu button on the joystick and press A or B.

 

For multiple disk games you need to enter Classic Mode in Settings.  You will then be able to swap disks during the game.

Watch the video below for more info on how to do any of the above:

 

https://youtu.be/Arax4gTb8xo

 

Firmware Update

 

Select menu Device settings > System information

The update file will be detected and you will be given the choice to Apply the update or Close the screen

If you choose not to update at this time, select Close. If you Apply the update, a screen will appear showing the update process:

Upgrade progress image

Do not interrupt or remove power while the update is in progress. After a successful update the console will restart automatically.