Does it mean that if I am currently holding BTC it will still be called BTC and if I want "altBTC" then I will need to go purchase the "altBTC". I assume the "altBTC" will still be based on BTC blockchain as ETC is based on ETH.

Still very confusing to me as more and more coins and used for this and that......currently I only know them as crypto-coins and used as a medium of exchange to buy an sell. Coming next are smart contract.....a bit above my pay grade at the moment.