To say 'X and I' use мІ с X (Instrumental), e.g. мІ с нљй 'she and I'. To say 'X and you' use вІ с X (Instrumental), e.g. вІ с нљй 'she and you'.
МІ с нќм гулїли по пђрку. He and I were strolling in the park.
МІ с нљй друзьї. She and I are friends. (She's a friend of mine.)
ВІ с нљй ходќли обљдать? Did she and you go out to dinner?