Note: before proceeding with steps below, set adapter bindings by following instructions here. Also insert operators sim card that does not work with device. For example if it's locked to operator "A" insert operator's "B" sim. Connect device to PC with USB cable

Launch DC-Unlocker client software.

Select manufacturer: Huawei modems, model leave as Auto detect (recommended).
Press "Detect" button (Big magnifying glass)

Wait for device to be detected

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” or "Do job" button

Wait for the device to be unlocked

After you see that device was successfully unlocked, restart it by disconnecting and connecting back. Now you can use it with any SIM card.