You can get started here. This is just the beginning but you need to do a lot more research to get familiar. More like read about how individuals lost Bitcoins due to some faults.
1. one person lost bitcoin on bitstamp exchange because the person didn't have 2FA enabled on their email and bitstamp admin removed his 2FA
2. another person lost eth by going to a phishing site and inputting private key
3. another person sent crypto to incorrect address due to some malware on their machine
4. a lot of people had bitcoin on mt.gox in 2013. exchange got hacked and they lost it all
5. bitfinex exchange got hacked but refunded customers
6. btc-e was shutdown but they were able to refund customers 63% or something
You get the picture. Not trying to scare you but be-careful out there. Use ad block such as ublock with firefox/chrome and anti-virus etc.
Start here:
https://www.coindesk.com/information/