The Minor scales have been classified mainly into three categories. They are Natural Minor, Melodic Minor & the Harmonic Minor.
Natural Minor three notes get flattened & they are E, A & B. For the scale C natural Minor we can write the scale structure as C,D,Eb,F,G,Ab,Bb & C.
For Harmonic minor two notes gets flattened & they are note E & note A. For the scale C Harmonic minor we can write it as C,D,Eb,F,G,Ab,B & C.
For Melodic Minor its a bit confusing to grasp. There is a clear difference in the ascending & descending order of the scale.
Ascending order is C,D,Eb, F,G,A,B & C
Descending order is C,D,Eb,F,G,Ab,Bb& C
This I have explained in the video attached here with.