1. Open 360 Security Guard, click the "More" button in the lower right corner, and then select "Full Functions".

2. On the function list page, find the "Computer Lock Screen" function and click the "Add" button.

3. After the addition is successful, you will see the "Computer Lock Screen" icon appearing in the lower right corner of the desktop.

4. Click the "Computer Lock Screen" icon to set a lock screen password.