The Dminor key is the relative minor to the key of F. If you understand that, then you can go to the 2nd of F which will be your Gminor . If you count up from F, you will discover that the 6 note is a D. If you go down a minor third from F ie: F-E-D, you will find the D note. The key to your issue is understanding chord allocation according to the scale. Not sure what your knowledge base is. But remember this. The 1st,4th and 5th notes in the scale has a major chord assignment major. The 2nd, 3rd and 6th notes in the scale has a minor chord assignment.The 7th note in the scale has a diminished chord assignment. It will always be that unless otherwise indicated. A math equation to help you remember this is this--1+4=5/major chords,2x3=6/minor chord. 1,4,5= major chord,2.3,6=minor chord. I hope that helped. This applies to all instruments,but most visilbe on the keyboard. Peace.