Can someone please explain if I want to buy crypto-currencies apart from bitcoin is it possible or do I've to first buy bitcoin, transfer it to exchange and then convert it?
Some cases you need to buy bitcoins first before we can buy other cryptos like altcoins for example. By simply buying some bitcoins you can be able to exchange it or convert it as what they always say intoba altcoins like ethereum, litecoins or whatever you want. But I know, these days, ethereum can now be bought on where you can buy bitcoins, ethereum it getting popular also that is why they are getting the attention too.
Yeah you can buy ETH on coinbase and trade that but the majority of cryptocurrency pairs are in BTC (the quote currency) so (apart from the length of time it takes to send BTC) it may be best just to buy bitcoin on coinbase, send to an exchange and then
buy your altcoins there.