I have calibrated my Tello, but the propellers are not on right. I cannot seem to put them on correctly as my motors are not marked to tell me which propellers go where.
It is not the motors but the propellers that are marked. Two will have a ridge and two will not. With your drown pointed away from you, place the ridged propellers on the front left and rear right motor shafts. Be sure they are snapped down tightly, taking care not to bend the shafts. This should help: