How to buy core online?

Excuse me, I'm a bit new to this cryptocurrency world and I'm trying to figure out how to buy CORE online. Could you please explain the process step-by-step? I'm interested in knowing where I can find a reputable exchange, what kind of information I need to provide for verification, and any security measures I should take to ensure a smooth and safe transaction. Also, I'm curious about the fees associated with buying Core and if there are any specific tips you can offer to help me navigate this process efficiently. Thank you in advance for your help.