i'm a begineer and don't know why this code isn't working help me

Question

Link: https://code.sololearn.com/c19sD2C1Lfkl/#cs
I would appreciate it if you showed me how to fix it.

Answer 1

C# isn't like Java. Procedure...
You're trying call sayHello(), but on this point it doesn',t exist.
You can define before (and declare after if you want), or declare before.
sayHeloo(); //doesn't exist
function sayHello() //now exist, but error for non existing got first.
{
}

Answer 2

https://code.sololearn.com/c5n4b582lDR9/?ref=app