Your NAMS operator name is supposed to be equal to your LDAP username, which is what you used to log in with. Check with the person who granted you NAMS operator status and make sure that they used the correct name. Enter the old password that you just used to log on with and a new password that you will use from now on. This changes your LDAP password. All of the NAMS forms have the entry fields crammed in at the top of the page.
Explanatory notes occur below the form itself.
If you are in doubt about what a field is all about, click on the prompt or scroll down to the expanatory note for that field. You can usually assume that a minimalistic input will work. The resulting table shows about everything the NAMS database knows about you.