The best way to use your Blue Yeti is to do so in conjunction with the Blue Sherpa app. The Sherpa app makes controlling the Yeti both easier and quicker, without the need to touch the microphone.  Consider the Mic Gain and Headphone volume knobs on the Yeti as the coarse gain control that sets the maximum level. You can then use the sliders in the Sherpa app as a fine adjustment from zero level to the maximum set by the knobs on the microphone’s body.  Generally, the best setting for the Blue Yeti is to have the Mic Gain knob set to about halfway. You can then use the MIC GAIN slider in Blue Sherpa to control the level of your microphone. As you change the position of the MIC GAIN slider you will see the peak level on the audiometer change.  For your ideal audio level, you want the meter to remain in the green and yellow. Adjust the slider so that the meter does not reach into the red. Make sure the meter does not hit the end of the meter on the extreme right. If that happens your audio will be peaking and may result in audio clipping and distortion.