How to change instruments (I imported a midi file and everything is piano + every 2 instruments are lumped together in the piano part and I need them to be independent)

You can replace each part with the correct instrument.
For each instrument name shown on the left, double-click to get the popup window “Staff/Part properties”
Under “Part properties”, click the button “Replace instrument”
On “Select instrument” screen, choose the correct instrument then click OK
Click OK on “Part properties” screen.

If you still have difficulties, it’s better to attach the MIDI file and your score (.mscz file). They contain much more information than a picture.

You can replace each part with the correct instrument.
For each instrument name shown on the left, double-click to get the popup window “Staff/Part properties”
Under “Part properties”, click the button “Replace instrument”
On “Select instrument” screen, choose the correct instrument then click OK
Click OK on “Part properties” screen.

If you still have difficulties, it’s better to attach the MIDI file and your score (.mscz file). They contain much more information than a picture.