QUES: Adjust the seat height to obtain an angle of 90 degrees between your body and arms

correct the punctuation.

CORRECTED: Adjust the seat height to obtain an angle of 90 degrees between your body and arms.

QUES: In short we prosper and thrive by cooperating free to focus on the things that really matter to us

correct the punctuation.

CORRECTED: In short, we prosper and thrive by cooperating, free to focus on the things that really matter to us.

QUES: The next step you

correct the punctuation.

CORRECTED:
The next step - you.