Please try the following:
Step 1. Open the internet browser on your notebook and input the following website address: https://findmymobile.samsung.com, click on the Sign in button and input your login credentials of your Samsung account, then click on Sign in button once more.
Step 2. The mobile device registered under your Samsung account will appear on the right-side of the screen. If you have multiple devices registered under the same Samsung account, make sure you select the device that needs to be remotely unlocked. Refer to the image below and click on the Unlock icon to unlock your device.
Step 3. Once you click on Unlock, a pop-up window will appear asking to verify the password of your Samsung account. After you input your password, click on the NEXT button, the pop-up window will automatically close and another pop-up window will appear with the result of remotely unlocking your device.