When someone gives you suggestions, they tell you what they think you should do.
Suggestions are usually helpful because they give you ideas about what to do.
Examples:
She gave me a suggestion for a good book to read.
Do you have any suggestions for what we should do this weekend?
I always listen to my mom's suggestions.
His suggestion to wear a coat was a good idea.
I have a suggestion: let's have a picnic in the park!
The suggestion to bring an umbrella was very smart.