First you have to define a key. You can use the menu Topic "New Key". It is dependent on your Application in which root key you define this key. I think a good place is anywhere below "HKEY_Current_User".
In the new key you can define new Values with the Types:
Integer, Float, String, Binary + (?). The Type is dependent on your needs.
But one thing: Do not modify an existing key if you are not absolutely sure what will happen. There are some Keys which control the starting of the System. If they are set wrong you will have a problem.
hnd
hasso55@yahoo.com