Okay first, the destination HUD is always

• the one with the latest version, and it will also be
  
• the one with all the toys you want to put inside (if you had other Signature toys to put inside), and it is
  
• the one that you will wear to start the transfer process, and that is kept worn during the entire process.

To start, simply click the Lulu logo on the HUD (or say "/1.") and hit "Transfer..."

Next, unless you're transferring stats from an old gag in an Armband, hit "HUD" for source HUD. It will ask you to rez the source HUD on the ground.

Now, question is, which HUD should you rez on the ground?

• when you're transferring another toy of a different type, the source HUD is the one containing that different toy.
  Example: You are wearing the cuffs HUD (destination), and you wish to transfer the gags over. You need to rez the HUD that contains the gags. Transfer will continue automatically, and the gags will be in your new HUD.
  
• when you're transferring stats from an old toy, the source HUD is the old HUD containing the same toy of the same type, but older version.
  Example: You just updated your cuffs and would like to transfer the old settings and stats over. You need to rez the HUD that contains the old cuffs. The stats/settings will transfer, but the old cuffs will not be transferred over.
  

That's it.