Step 5: Solder your switches/plugs
The 10k pots are always tricky, the "lone pin" of the three (the middle) is the input, and one of the other pins goes to power and the other to ground.
Solder a switch to a 9volt battery clip for the receiver .
The transmitter, if housed in a SMALLS tin will need a N-type battery holder, to save space no switch is included (I just put the battery in to turn it on) If you can't find a N-type battery holder you can simply solder the leads to the battery terminals then to a switch, just be careful not to get the battery too hot with a soldering iron or see if hot glue will keep good battery contact.
OR you can easily house the transmitter with a 9 volt battery in a normal size Altoids tin. The advantage of using a 9 volt will be apparent when you start burning through A23 batteries in 25 min haha.
P.S. the transmitter circuit also works with a "wal wart" power adapter if you wanna config your spy setup to plug in, you could invent a cool lamp or radio or something that has a laser transmitter in it that operates when the power is turned on or even use a PIR motion sensor to turn on your transmitter when people are in the room!! MUWHAHAHA