• Cats should be transferred in an enclosed space, such as a shed, garage or a room in a house or office, in case of escape. Make sure all windows and doors are securely closed.
• Ideally both pieces of equipment will have guillotine end doors. If not, you'll have to improvise, keeping safety, security and escape prevention in mind at all times.
• If either piece of equipment has any doors other than the one that you are using for transfer, ensure they are securely closed and locked.
• Position the back end of the cage against a wall, or some similar kind of solid object, for support. This helps to prevent either piece of equipment from moving during the transfer process - the cat may escape if either moves.
• Next put the door end of the covered trap hard up against the door end of the holding cage.
• Make sure both pieces of equipment are covered.
• If you've an assistant, get them to support the trap hard against the cage, again to prevent movement of the equipment. If you've no help, it's best to support the back of the trap with your foot and leg (this can involve a few contortions but you soon get used to it).
• Make sure that the two fronts are touching and will not separate, as described.
• Open the front of the trap and the front of the cage simultaneously.
• Then remove the trap cover.
• The cat should go toward the 'safety' of the covered cage.
• As soon as the cat enters the cage, close it's door, making sure you don't catch her tail in the process.
• If there's any doubt about the security of the door, cable-tie it shut.

It's surprising how often cats will obligingly transfer themselves from trap to cage. But some can be reluctant. If they won't oblige, blowing behind them, towards the cage, can encourage them along. Poking them (gently!)  in the right direction with a locking rod, or some kind of pokey thing can also help - though be sure NOT to use a locking rod from the cage you're transferring them to!

And, of course, this method can be used when transferring an animal between any types of equipment such as traps, cages and/or pens.