I’m just a beginner when it comes to audio editing and mixing and this question may be very obvious to lots of you, 
but I want to add a tremolo to a generated sine wave,
but I want it to be the exact same BPM as the song file i’m working with (which is 146 BPM) so the song sounds fuller and nicer.
As the tremolo tool has a frequency option, how do I convert BPM to frequency? Please let me know! 
how do I convert BPM to frequency?
Frequency (Hz) is cycles per second and BPM is beats per minute, and as you know there are 60 seconds in a minute. So for example, 120 BPM is 2Hz.
F = BPM/60
I want it to be the exact same BPM as the song file i’m working with (which is 146 BPM) so the song sounds fuller and nicer.
That could be tricky and I wouldn’t be surprised if you are off by the end of the song, especially if the music made digitally or if there was no metronome or click track and the timing varies a bit.