Equivalent exposure value chart. Print this out and you may find it useful to help you quickly find all the different ways to achieve the same exposure in terms of different aperture and shutter speed values.
Just a reminder of my analog long time ago course, only with digital. "Learning to shoot in manual doesn't have to be scary or confusing with these simple steps. Learn what aperture, shutter speed and ISO means.
Learn How To Shoot In Manual Mode - ISO, Aperture & Shutter Speed Explained
To be comfortable shooting manual you will need to know what your necessary adjustments are. Though these settings are all numeric, there isnt some insane math equation that you need to do to find out what to dial them