If you have a Dm chord playing on the back.
You can play different scales over it to bring up distinct “flavors”.

The D minor Scale or D Aeolian has the notes: (D - E - F - G - A - Bb - C) which are relative to the F major scale.

If you want to play a D Dorian you play the notes: (D - E - F - G - A - B - C) which are relative to the C major scale.

If you really want to understand the Modes and be able to used them, you should stop thinking of them as a major scale starting on a different degree.

Instead you should think of them as separate scales with their own step structure and interval types.
Trust me, I didn’t understand the whole modes thing until I realized that they are scales on their own right.

I’ll be glad to give you some guidance if you start a thread in the Music Theory section of the forums. :)