Hmm. Ideally I would recommend you get used to the interface and usage of LMMS before trying these sort of effects.
EQ is short for equalizer.
See if this helps you:
https://drive.google.com/file/d/1Wb4udh ... sp=sharing
(For high quality viewing, click "gear" icon and change "Quality" from "Auto" to the highest quality possible. Otherwise, download it for clear viewing. I have uploaded a clear file.)
It would be more helpful if I spoke alongside about how the EQ works, but for now you'll have to work with text.
If you do not understand how the equalizer itself works, then you need to spend more time around LMMS and understanding the behaviour of different tools like equalizer. Tutorials will help.
If you have any doubts about the process itself you can ask and I can post a better video (my screen recorder didn't capture me adding the equalizer, because that opens in a different window.)