I’m a electronic drummer and need to learn how to remove all sort of drum beats (kick, snare, toms, cymbals, hi hats) from a sound/song track. Can any expert teach me how? Thanks in advance. 
Sorry, that can’t be done. 
“You can’t un-bake a cake or un-fry an egg, and you ca’t un-mix a song.”
You can isolate the left & right channels, you can remove everything in the center by subtracting left & right (that’s how “Vocal Remover” effects work), and there are some tools to extract/isolate the “center” channel. And, there are very-limited things you can do with frequency-filtering. (But, there is a LOT of frequency overlap between the instruments.)
Pros record in multi-track where each instrument & vocal is essentially a separate recording. That way they can edit/process each element separately, or re-record various instruments, etc. That wouldn’t be necessary if they could record the whole band with one mic and separate everything in software.
P.S.
You might be able to do something with MIDI versions of songs. As you may know, a MIDI file contains the notes & timing for various instruments, and the instruments are synthesized at playback time. Audacity doesn’t support MIDI (and I don’t use it, so I can’t help you), but with the appropriate software, you may be able to download a MIDI file and edit it to remove the drums.
@ DVDdoug, thanks. I hear ya, but seemed a bit complicated to learn. Alternatively, any good website to download free drumless tracks or cheap ones that has some latest hits? Appreciated it.
Internet search: tracks without drums - Google Zoeken .
Gale