There's some through hole & surface mount soldering to be done, but when you're finished you've got a sparkly eyed Hackaday head lapel pin.
Your blinky badge kit comes with the following parts:
To assemble the kit, you'll also need a soldering iron, safety glasses, wire cutters, tweezers, and solder flux.
The switch goes on the right-hand side of the back of the badge. The switch lever points outwards.
Tin the pads on the side of the switch. These pads are for mechanical stability. Don't use too much solder.
Apply solder to the three small pins on the back of the switch. These provide the electrical connection to the battery and LEDs.
Place the battery holder over the large circular pad. The small metal 'nibs' of the battery holder go over the square pad. Make sure the 'open' part of the battery holder points toward the bottom of the badge.
Solder one side of the battery holder, then solder the other: