There are many altcoins today and how many are you looking into investing? also are you investing for long term or not?. Nevertheless, to throw a random answer, since you don't know the type of altcoin you want I think it's better you start with top altcoins like ETH, XLM, BNB. The reason is this, they are already developed and growing thus will make you more relaxed unlike new altcoins which are filled with many uncertainties. In addition, I would suggest you take your time and study more about altcoins this will make you have an idea of what to lookout for in case you consider investing in new altcoins.