After you have added a site, you will probably want to add some login details. By default, for each new site a login is created named "Main Login". Create a new site to see this (or lookup a current one). Now under the headings "username", "password" and "comment" you can record your login details (see fig. 1).
fig. 1
Once you have entered the data, click "Save Login" to save those changes to the current user. One way of using this program if you are worried about other people using Copernicus to read your passwords (if you are not using Encryption) is not to store your exact password, but something that will remind you what it is eg. "main-pass".
You can create additional logins easily, simply by clicking on the "Add Login" button as shown in figure 1 and giving it the name you want. Don't forget to actually Save the File if you want your changes to be permanent.