Launch DC-Unlocker client software
Select manufacturer: ZTE modems, model leave Auto detect (recommended).
Press "Detect" button (Big magnifying glass)
Wait till DC-Unlocker fully detects device
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, do not enter username and password, only click "Check login"
Open Unlocking tab, click “Unlock”
Wait till you see a message that modem is unlocked
After you see that modem successfully unlocked, restart it by disconnecting and connecting back. Now you can use it with any SIM card