1. Download the jar file patch.
Move (.jar file) to bin folder where the IDE is installed.

2. Open (bin/.exe.vmoptions) file, for example for me its at
C:\\Program Files\\JetBrains\\WebStorm 2017.3.5\\bin\\webstorm.exe.vmoptions

WARNING: if you installed IDE only for your current user, then you have to edit .vmoptions files that are placed in %USERPOFILE% folder!
For example,
C:\\Users\\YOURUSERNAME\\.PhpStorm2017.3\\config

3. At the end of this file paste this and save (replace path to .jar file with your path, make sure it doesnt have quotes)

-javaagent:C:/Users/maxst/JetbrainsCrack.jar

REPLACE BACK SLASHES WITH FORWARD SLASHES.

4. Do the same for bin/64.exe.vmoptions file, paste the same into this file as well. Again, if you have IDE installed for your current user, edit file inside %USERPOFILE%\\\\config

5. launch your JetBrains product, use Activation code as an activation method and put anything as activation code.