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.
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.
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.