Newbie here and I want to start trading soon. Just want to get tips on when to invest on btc and eth. thanks in advance!

In the first place know what bitcoin is there usages and its features then second Find out what Ethereum is too. However, while learning and studying those two, you can try to invest in Eth while the price value was cheap then hold, and even Bitcoin you could also buy it in the amount you can afford to do so.