Question 1:
Software install tool should be in Kmenu -> Configuration -> Packaging
go to
easy urpmi to add network software sources. it will tell you how to add sources to urpmi.
Question 2:
You don't really want to log in as root, open a terminal window and type "su" then your password. this will make you root in that window, you can then launch whatever apps you need as root.
Question 3:
Go to Mandrake Control Center by clicking on Kmenu -> Configuration -> Mandrake control center. You will be prompted for the root password. From here you can do virtually all your config and setup it also has a software menu to launch install software, remove software . . . ect
For configuring your screen resolution, once you have Mandrake control center running click on Hardware and you will see a tool to change screen resolution.
Also if you want it to prompt you for a username and password on a graphical menu when you boot you have to set it up in Mandrake control center click on "boot" then "Drakboot" then click on "no, I don't want autologin".
I would also change your GDM (Graphic Display Manager, this where you put in your username and password) The default is MdkKDM, I have seen problems with it. In Mandrake control center click on "Hardware" then "Choose the display manager" (It's a stop light Icon). I would select "KDM" It works great.
Questions are NOT stupid, that's what we are all here for. A lot of us may tell you to search google and search the forum, but that's usually when we know the question has been asked many times.