Hi Navarro!
I'm in an orchestral training band without a rhythm section, so its all about the counting in. Be sure to know how many bars the intro takes, and when the conductor begins, - some people tap their foot to keep the beat and the count, personally I count the beats in my head, and the tighten one finger at a time to acknowledge how many bars have completed so that I know when to come in.
Playing the Tenor means that, like you, I am predominantly playing a base line, which in itself can be quite satisfying, especially when you are the only one with that specific part to play - an example is one right now where the baritone horn plays one beat while I rest, and then they rest while I play the next beat ....... a bit of a oompa bounce I guess, but it sounds really great and makes the whole christmas song sound really happy.
I work with the metronome as much as I can at home, though I find it challenging to do that as my electrical one isn't loud enough so I lose the idea of it, and the mechanical one is just plain awkward to get going right. I find it much easier to observe the musical director/conductor in front of the band and keep my timing there so very much better.
In my first few weeks at the band though, this was all a bit elusive while I was settling in. Two months in, and I'm thoroughly enjoying every single session and the challenge of playing dots that have literally just been given to me a moment ago.
Give yourself a break HJ! You have to give yourself permission to adjust to any new group - you know that as much as anyone. Imagine it was someone like me asking this question, and how you would answer me - then take your own advice
Your pal Mel