Download drivers for ZTE F102 here
Launch DC-Unlocker client
Select ZTE phones, select model Autodetect (Recommended) and press detect button - big magnifying glass
Wait for the phone to be detected
NOTE: If you can not detect phone, make sure it has been fully installed on computer. It must be visible in device manager under "Modems" and under "Ports" lines. If phone has visible drive/cdrom in computer, then right click on it and select "eject" from menu (make sure you have first installed everything from it)
Open Server tab, enter your username and password that you received after credits purchase. Click "Check login". (you can buy credits here www.dc-unlocker.com/buy). If DC-Unlocker/Vygis/Rocker/Infinity dongle is connected, only click " Check login "
Open "Unlocking" tab and click Unlock button
Wait for device to be unlocked
Now your phone is unlocked and will work with other Operator cards after restart