1. Teflon tape (it is not recommended to use thread sealant)
2. 19mm wrench for the 1/4" to 3/8" adapter. And a 24mm for Mosmatic couplers, or 1" for MTM couplers. DO NOT use pliers, or adjustable wrenches. You will NOT be able to get the connection tight enough.
3. Workbench with vise is preferred, but not necessary.
1. Put 7 wraps of Teflon tape on the male 3/8" end of the adapter.
2. Use the 19mm wrench on the adapter, and brace on the ground or clamp in a bench vise.
3. Use the 24mm (or 1") wrench to install the coupler by pushing against the other wrench. You will need to really put your weight into it and get it TIGHT to prevent leaking.
4. To start the process of installing the adapter into the Comet hose, make sure the threads are clean with NO tape. Hand tighten and proceed to step 5.
5. Use the 19mm wrench on the adapter and a 19mm wrench on the Comet Hose end to install adapter and coupler into Comet Hose. Don't go crazy here, but get it nice and snug. You may need to make it a bit tighter after you test the system for leaks.
6. Make sure everything is connected (water inlet, sprayer/wand/nozzles, etc) and test system and check for leaks. If leaks occur, try torquing things down further. If leaks still persist, repeat steps 1-5.