Hello and welcome, please check this Unity Community Code of Conduct - legacy and code formatting post here Using code tags properly
It literally means it expected ‘;’ at the end of line 6.
//This is bad
public Rigidbody rb
// This is good
public Rigidbody rb;
If you are new to coding and C# in general it would be good if you check some documentation or basic tutorial, also this is very general coding question and it would be good to post such questions here https://stackoverflow.com/ or even better to google them first.