How do I buy & deposit bitcoin?

As a crypto enthusiast seeking to expand my portfolio, I'm curious about the process of buying and depositing Bitcoin. Could you please elaborate on the steps involved? Firstly, which exchange platform would you recommend for its security and ease of use? Secondly, how do I set up a wallet to securely store my Bitcoins? Lastly, could you walk me through the process of purchasing Bitcoin and depositing it into my wallet? Any specific tips or advice you could offer to ensure a smooth transaction would be greatly appreciated.