You will probably find the ket of a dorian [ AMINOR]easy enough. find notes a c e[ aminor ] e g b[ Eminor]gbd [gmajor]C E G [ c major], F MAJOR F A C , d minor d f a. then practice the scale of a dorian, a b c d e fsharp g a. .
then practice the scale of a major, a b csh d e f sh g sh a.then the chords of a major a csh e,d major d fsh a. e major e gsh b.f sh minor f a csharp. also make a diagram of your fingerboard. Dick Miles