Hi and welcome. Your Hoxton is a privately branded eGo style rig, using a clearomizer (the tank part on top) with replaceable dual coils. The coils are wear parts and will eventually either stop working or burn from the heat and taste foul, so they will have to be then replaced. Your battery will fit any eGo threaded clearo-- there are tons of them, and most of them are better than what you now have-- but is not powerful enough to safely drive any coil below 1.6 ohms. In general, the lower the ohms, the more and warmer the vapor is produced. Lower coils also burn more juice per puff.
Changing flavors is easy. You can just put the new flavor in the tanks and vape away. The taste will be "interesting" for the first few hits, but the new flavor will eventually overwhelm the old one (except in the case of very strong flavors like menthols or cinnamon or something) and you'll be vaping on the new one. Or, you can disassemble the tank and wash it clean in hot soapy water. The tank must be completely dry before re-use. Don't wash the coil like that, remove it from the base first if you intend to reuse it. To clean a coil, soak it overnight in pure grain alcohol or high proof vodka, then rinse well in hot water. It must be completely dry before reuse; let it air dry overnight on a paper towel, or they can be force dried with a hair dryer. Even after cleaning, the coil will probably retain some of the old flavor. Therefore you can re-use it and put up with it for a few hits, or you can put in a new coil. Some people will keep several coils and change them as they change flavors, washing the tank each time.
