What's next after buying crypto coins?

Depends on what's your goal and investment thesis of course. If you're trading, follow your trading plan. If your hodling, just reevaluate along the way if your coins are still worth holding. You can take profits along the way or just hodl till the end of time, see what's comfortable for you.

You can take profits when you feel your investment thesis doesn't hold anymore or if you feel like the market is going into a winter you can also take profits. Alternatively, if you choose to hodl, you can always earn 'interest' on your crypto using platforms like Nexo, Celsius etc or DeFi platforms. Alternatively, not sure if Coinhako has it, you can use that to stake some of your coins to earn on them. This will allow you to slowly increase the pool of coins that you hold. Most staking interest rates would be anywhere between 2% to 20% a year depending on the coin. It doesn't sound like much, but hey, you're gonna hodl anyways, might as well.

Most news sources are kinda biased so just take in a range of news sources. The standard coindesk/cointelegraph is decent for general crypto news. To add on to that, just follow a bunch of the larger players on Twitter. If you're keen you can also take some info from telegram chats or /r/cryptocurrency on Reddit. Take note that everyone there is a stranger though and likely have their own agendas. Crypto is really a dog eat dog world so dyodd and assume everyone is a scammer or shilling their own coins hahaha.

If you're hodling, you probably don't need another exchange unless you're looking for other coins. However, you might want to consider an external wallet too if you're holding a substantial amount of crypto. This will allow you to keep your coins safe (provided you are safe on the internet lol). As the popular saying in crypto goes, "Not your keys, not your coins".

Just keep up to date with your coins and if you're keen you can look into DeFi. It's quite hot lately but I think it's quite an interesting development to look into especially if you wanna gain more interest on your coins or look into the possibilities in the DeFi space.