You're right, that must be the weirdest instructions ever
What a chromatic tuner does is display the nearest note (C, C#, D etc.) and possible octave (C2, C3 etc.) to what you are playing AND list how much "cents" (100th part of a semitone) you are off OR display some sort of needle indicating how much you are off. Then just tune up or down so that the note displayed is the one you want for that string, then move on to the next string.
Make sure that ur tuner is on "auto" setting if there is such an option. There may be some other values on the tuner that you can mess with, such as the reference pitch (which should just be kept at 440 Hz) and in some cases the key (setting this to something other than C is not recommended). It's (supposed to be) really easy!
