Go for John Guest fittings; barbs are a pain and prone to weeping. Okay, I found my old shopping list from when I first started. You'll need the following. Kegs: As many as you can afford (and that won't be enough, trust me). CO2 Bottle: You need one. I have three; one is in use, one spare and one for forced carbing. CO Gas Regulator: One for each cylinder in use. These have a 3/8 inch screw outlet. John Guest 3/8 inch Screw to 3/8 inch push-fit: One for each regulator. Part number is PI451213S 3/8 Inch Tubing: Work out your run lengths and add a bit for errors. A hint is to try and get different colours for gas in and beer out; it helps when you've got a whole bunch of kegs! You need to run from the CO2 cylinder to the keg gas in disconnect, and then from the beer out disconnect to the tap. A portion of the beer out run might need to be 3/16 tubing: more about that later. Grey Gas In Disconnect: One for each keg. These have a 7/16 inch screw fitting. Black Beer Out Disconnect: One for each keg. These have a 7/16 inch screw fitting. John Guest 7/16 inch BSP to 3/8 inch push-fit: One for each disconnect. Part number is PI4512F4S. Note that this is actually a 1/4 inch FFL thread to 3/8 inch push-fit, but it is the right one! Tap: One for each keg. You can either get a picnic/party tap (effectively a cheap plastic tap on a length of tube), a disconnect tap (a tap with integral disconnect, but expect plenty of foaming with one) or a decent tap that is mounted. If going for the latter, forward sealing taps are the best option. OPTIONAL PARTS 3/8 inch to 3/16 inch Push-fit Reducer: Two required for each beer out line. You might not think you want these, but when you're looking at a glass of foam you'll realise you do! I added around 1.5 metres of 3/16 inch tubing in the middle of each beer out line. I simply coiled the tube up and used to tap to keep it neat. The reduced diameter slows the flow and prevents excessive foaming. Part number PI201206S. 3/16 inch tubing: See above; you'll need around 1.5 metres per keg. Line Splitters: I run four kegs off a single CO2 bottle, using three two-way push-fit line splitters. Part number PI2312S. The alternative is a much more costly manifold. The best way to buy the John Guest fittings is via plumbers or on-line suppliers. Buying in bags of 10 is best as individual parts from homebrew suppliers can be more costly. The surplus parts can either be sold or retained for when you inevitably buy more kegs. Okay, you sanitise your keg, fill with beer, fit the lid and holding it in place give a burst of CO2 to seal. Then release the pressure and let it refill a few times. This purges any air and ensures there's only CO2 on the beer. You then have two choices. Either set the CO2 to 10psi and leave to carb for a few weeks or turn it to 30 psi for 5-7 days. If the latter route is taken, before you set it to 10psi for serving release all of the pressure. This stops the higher pressure in the keg pushing beer into the regulator, which will kill it off. You can fit non-return valves but just ensuring the pressure in the keg is lower than the bottle will prevent flowback! Once carbonated, drink.