Simple admin attributes filter extension adds simple filter to attributes and attributes groups listings in admin area.
If you are using OpenCart 1.5.x then you will need to install vQmod extension. You can get it HERE.
Just copy xml file to vQmod xml folder.
If something goes wrong – you can rename .xml file like .xml~ (it will disable plugin) and then contact me with your issue.
If you are using OpenCart 2.x then you can use integrated modification engine.
Just open Admin backend and go to Extensions -> Extension Installer. Upload ocmod.xml file. Then go to Modifications and press the Refresh button.
That’s all. Extension is enabled now.