There's a lot of things you need to consider that if you don't give importance your investment may be at risk so here are some of the things ou need to consider or to study.

Learn about the basics first such as:
• Bitcoin wallets
• How Bitcoin works
• What is Blockchain
• Types of wallet
• And different kinds of investments
 
Second Learn what kind of investments you need to do, here are:

• Trading
• Holding

When you've decided what kind of investment you're going to do start finding exchange where you will bought your first bitcoin there's a lot of platforms where you can buy bitcoins such as:

• LocalBitcoins
• Binance
• Coinbase
• Just search on the internet.

NOTE: You should know the risk you're going to face when it comes to investment remember that there's no assurance that if you invest you're going to earn so invest only what you can afford to lose.