I have a dataset set up with 3 fields, ID, username and password. I want the user to type in a new username and password and this then gets saved back to the dataset. 

How do I take what has been typed in and save it into the data set?

So far this is the code I have

usersTableAdapters.UsersTableAdapter user = new usersTableAdapters.UsersTableAdapter();

user.usersDataTable usertable = user.GetData();

This allows me to connect to the data set although I am not sure how to take the values the user will enter in the input boxes and save them back to the dataset?