There are 2 possible ways to disable Window Defender, You can choose either One.

Disable Firewalls
Press Windows key + R
Type "CMD"
Run it as administrator
Paste the following command

NetSh Advfirewall set allprofiles state off
 
Press "Enter"
You should see "OK"
Now your firewall is disabled

 

Disable Windows Defender
Download the Defender control app
Extract it to your Desktop
Run DefenderControl.exe
Click on "Disable Windows Defender"
 

HERE IS the Video To Do It Manually!