I have been told that I should be able to tap my feet, say "One and Two and...) and have a metronome going all at the same time. This way I always know what beat in the measure I am on. Now, for me at this point If I try to count AND listen to what I am doing and tap my feet in time, I find this pretty difficult, ESPECIALLY talking to myself (even silently) and listening to myself play. All while listening to the metronome. Does this all come together and do you stop counting at some point in your career ?
You can make all of these come together, but it won't just happen, it does take practice. To take a step back though, there are several things you're trying to accomplish by doing all this.
- You're trying to play the correct rhythm.
- You're trying to place your beats accurately at a steady tempo.
When you practice counting aloud (or internally, or tapping... I would argue that you don't need to do more than one of these as long as you have learned to count out loud), you are working both of these. You eventually become able to speak or think or tap the count accurately without mental effort, and you don't necessarily have to keep counting with numbers. You may be "counting" by thinking, "Boom, tack, thumb, whap." Some would argue that this is sloppy and should be avoided. If you're playing classical music they're probably right, but if you're playing hip hop, it's fine.
For a newer musician this counting can be difficult and frustrating at times, but if you just focus on the specific measures--or beats--that give you problems you will find it gets easier every time. A trick drummers learn is to work on parts separately, i.e. just play the right hand part, then just the bass drum part, then try those two together, then play just the left hand part, then the two hands together, etc. Eventually it just clicks.
As for the metronome, everyone tells you how great they are for helping you keep a steady tempo, and it's true, but metronomes do require yet another learning curve. The first hurdle is learning to play your piece with the metronome at its tempo, which usually forces you to make some changes. But the trickier problem occurs when you are playing and begin to drift off the beat. It's not very difficult to realize you're off the beat, but it does take practice to be able to identify whether you're ahead or behind, by how much, and how to correct yourself. But again, the hardest part of learning is the first try and with some practice you will find that you notice smaller amounts of drift and can correct more quickly and easily.
And as you point out, you are supposed to do all this while listening. This is easy to say, and is not easy to do but if you practice your parts enough, building up to being able to count through them effortlessly, then learn to play with a metronome comfortably, you should be able to shift your attention to the ensemble.
However, you rarely play with an ensemble and a metronome, you usually do one or the other. If you're the drummer, you are the metronome, otherwise you will be matching the beat of the ensemble instead of a metronome.