When you choose a lantern to use in a production, the most important step is to visually inspect it to make sure there it is safe to use and reliable.
look at the outside of the lantern , has it got a current electrical test tag or PAT tag on the mains cable. If there is no tag or it is out of date, have it tested and tagged before use by a competent and authorised person.
The lantern may have been damaged since the PAT test so inspect the mains cable for any cuts , including where the cable goes into the light and check the plug is in good condition. There should not be any sign of the internal wires.
Look at the yoke, check the tilt locks, make sure the hook clamp has the correct bolt, washers and wingnut or nylock nut. The lantern has to have a safety wire. Check that the focus controls move freely, any accessories such as barn doors have tight leaves that stay in place. If the lantern is a profile and has shutters, make sure the shutters are in the correct slots and are easy to move into position. If you are using gobos, check that you are using the correct size gobo holder for that lantern.
If you have dual wattage lanterns such as 1000W/1200W zoom profiles, check that the lamp fillament is at the correct height, look at the lamp base spacers.
Once you are confident that the lantern t is safe and functional, check that the lantern works, then fit the gel if needed, then put in a safe place until needed. If it is a DMX controlled lantern you will need power to set or check the DMX start address and the mode. Put the fixture number, universe and DMX address on a piece of tape on the lantern so the details can be checked with the power off. You can put a tape label on the conventional lantern yoke giving rigging location, function etc if you are prepping a large number of lanterns.
When you are rigging a stage, have a safety plan in place to prevent injuries.
When you place the lantern on the lighting bar or boom, check that no mains cables are trapped underneath the hook clamp. Make sure the lantern is the right way up, with the focus know on the bottom. Some brands of theatre lamps will fail if run upside down. The Selecon Acclaim 650W fresnel has a safety wire knob at the top of the lantern that can be confused with the lamp focus knob on the bottom. Tighten the hook clamp, attach the safety wire, open up any barn doors or shutters, then point the lantern at the stage focus point, to make it easier to identify lanterns and check the lighting plan. Make sure that conventional lanterns plug into dimmer channels and DMX controlled lanterns go into hard power. Dress your cables with loops or tape but leave enough slack for the lantern to move freely for focusing. Choose the correct length cable for neatness and to assist if troubleshooting is required. Label each end of extension cables and DMX signal cables, before it becomes spaghetti city.
Do not rig conventional lanterns and DMX lanterns too close to each other as the heat from the conventional lanterns may cause overheating and damage to the DMX lanterns.
After you have rigged the lighting bar, patch the circuit numbers into the dimmer sockets. Then if it is safe you can bring the dimmer channels up to test the lights work and the patching is correct. This is known as flashing.