RBA's are rebuildable decks designed to suit what in normally a stock coil tank. The main difference between an RDA or an RTA is the smaller size of deck to build upon.
RBA's can be an excellent entry point to the DIY side of vaping. Using your stock coil tank. by purchasing the suitable RBA for that specific tank, you can learn and practice, making and installing your own coils.
As touched upon, the main difference with an RBA when compared to an RDA/RTA/RDTA is the build-deck is smaller, as it has to fit into the tank itself, whereas the deck of an RDA/RTA/RDTA is larger with the Top Cap fitting on top of the rebuildable deck with full width of deck.
Being smaller, means more fiddly. Don't let this put you off though, RBA's are a low cost opportunity to hone your skill, before making the choice to upgrade to RDA/RTA/RDTA.
The methods of building are the same on RBA as it is for RDA/RTA/RDTA. You will require either Wire or Pre-made coils, Cotton and essential tools, we would always recommend purchasing a handy Tool Kit.
RBA's have become popular once again, with the in-fashion AIO Pod Systems and Billet Box styled devices.
There are vast amounts of tutorials available on the likes of Youtube which can teach you how to make your own coils and install and prepare. Vaping 101 also has it's own Youtube channel where you can find many videos showing Andrew building coils for RDA/RTA etc The process is the same for an RBA, please take a look here Vaping 101 Youtube Channel.