The video linked in the top-most comment will beautifully answer your questions. It's also on YouTube. You can think of it as in the sampling rate provides a m

The video linked in the top-most comment will beautifully answer your questions. It's also on YouTube. You can think of it as in the sampling rate provides a mathimatical solution to the waveform - it's simply 100% accurate all the time. The bit depth adds extra "buckets" to divide the volumes into . If you have 2 bits, you then have volume levels 0, 1, 2, 3.