For 8 of the 12 major scales changing to minor does not change the fingerings. There are simple rules for forming minor scales.
Simple minor (also called ascending melodic minor and jazz minor) simply lowers the third note of major scale by one half step. For the most basic example, C major changes to C simple minor by lowering the third note, E, to Eb. Nothing else changes, and the fingering does not change. We describe this as major with b3.
(Note: when a degree of a scale has the symbol “b”, it does not mean the same thing as a flat sign in notation. Instead, it means to lower the note. If the regular note is a sharp, it becomes a regular white key. If the note is white, it goes down to either a black key or another white key. (In the rare case that note starts out as a flat, meaning a black key, lowering it will drop it down to the next white key. This is called a double b, with the symbol “bb”. When playing scales, simply remember that lowering a note in a scale means going down exactly one key, a half step.)
Harmonic minor lower the 3rd and 6th notes of the scale. We describe this as major with b3 and b6.
Natural minor lowers the 3rd, 6th and 7th notes of the scale. We describe this as major with b3, b6 and b7.