XNA missing files in visual studio on monogame project MacOs

i’v installed visual studio 2017 for mac and monogame,ang i get this error:

Error CS0234: The type or namespace name ‘Xna’ does not exist in the
namespace ‘Microsoft’ (are you missing an assembly reference?) (CS0234)
(SpaceShip).
i’v seen some solutions for windows users but not for mac.i hope can anyone help.