timing on 1990 Plymouth Acclaim

i need to know how to set the timing on a plymoth acclaim 1990 v-6 with ac i know the tops have to be in line with the notches but the bottom i had to take the sigh off to get to the timing belt cover so do i need to put it back on to time it

Asked by for the 1990 Plymouth Acclaim
Place transmission in NEUTRAL and turn OFF all lights and accessories.
Connect timing light to number 1 cylinder. Refer to timing light manufacturer's instructions for proper connecting procedures.
START engine and allow to warm up to normal operating temperature.
Coolant Temperature Sensor , Disconnect coolant temperature sensor electrical connector on thermostat housing. The CHECK ENGINE lamp on the instrument panel should illuminate once this sensor has been disconnected. Coolant fan will come on and stay on throughout the procedure.
Check timing at the front crankshaft pulley. If timing is within 2~ of specifications do not adjust. If timing is incorrect, loosen distributor hold-down bolt and rotate distributor housing until correct timing specification is obtained. Refer to SPECIFICATIONS . Basic Timing 12°BTDC
Tighten distributor hold-down bolt, and recheck timing. Reconnect coolant temperature sensor electrical connector, and erase any fault codes that may have been set.