All the modes derived from the major scale can be played in many different positions on the fretboard and in any key. Just as there are twelve major keys, there are also twelve possible starting notes for each of the modes. Any note of the chromatic scale can be used as a starting note for any mode. This requires a knowledge of the formula for each mode. The scale degrees of each mode are listed here.
If you are serious about using modes in your playing it will be necessary to memorize the formula for each of these modes. Take one mode at a time and learn the formula as it relates to the sound of the mode. Learn the fingerings for the mode and experiment with it.
Learn the licks which are given at the end of each group of fingerings, and then listen to your favorite recordings and try learning some solos which use each mode. In this book all of the scales and modes are written with C as the starting note, as this makes it easy to compare them.
However, it is important to eventually learn all modes in all keys. All you need to work out a mode in any key is the starting note and the formula. As an example, here is the Dorian mode shown in four different keys.