How can I give a speech about how Cristiano Ronaldo achieved his dreams by overcoming adversity?

This sounds like the speech of appreciation that I make my public speaking students perform.  It sounds like you need to explain why you appreciate Ronaldo, which means you are going to mix informational facts about him and persuasive opinions of your own.  The persuasive opinions of your own will be easy to do by simply concentrating on the positive aspects of him.  

Before you begin outlining your speech, pick three events in Ronaldo's...

This sounds like the speech of appreciation that I make my public speaking students perform.  It sounds like you need to explain why you appreciate Ronaldo, which means you are going to mix informational facts about him and persuasive opinions of your own.  The persuasive opinions of your own will be easy to do by simply concentrating on the positive aspects of him.  

Before you begin outlining your speech, pick three events in Ronaldo's life that you believe helped shape him into the person/player that you admire so much.  Your speech will contain those three items, and it covers the teacher's requirement to talk about specific events.  Because you chose major events that helped make Ronaldo great, you have built in the ability to conclude with your own opinion about achieving your goals by following his example.  

To start your speech, you need an "attention getter."  Some teachers call it the hook.  Regardless, the first words out of your mouth need to get your audience interested.  If they are not, they will not listen. I teach five attention-getting tools.  

1. Make a bold statement.  Lean toward opinion here.  Facts are seen as boring. 


2. Use a quote.  For you, I recommend using something Ronaldo said or a famous quote about achieving your goals.  


3. Give a definition.  I don't see how this would work well for your speech.  Stay away. 


4. Ask a question.  It's simple and effective, because it forces your audience to immediately engage mentally with your speech. 


5. Use an anecdote.  Tell a brief story that ties into your speech topics.  

After your opening attention getter, then you will move into the body that contains the three main things about Ronaldo that you want to talk about.  Pre-plan your transitions that move you from main point to main point.  Those must be smooth.  In your conclusion, emphasize why Ronaldo matters to you and why his example can inspire your audience as well.  Good luck and have fun!