Here's a brief review of 'Extending the Major scales. The C major scale looks like this.
We can extend the range of the scale across all 4 strings like this.
The Dorian mode of C major (D Dorian), extended over all the strings, looks like this.
When you combine both patterns you get the following pattern.
Note that these are all notes of the C major scale. Using the modes you don't need to remember the entire pattern you only need to remember the Ionian and Dorian modes and their starting positions. Now let's move on.