1) This link shows how to setup a desktop system (which has probably been done for you, but maybe it'll help with and additional setup you need) - http://www.howtoforge.com/the_perfec...07_spring_free
2) How to print grid lines - http://openoffice.blogs.com/openoffi...playing-t.html
3) Unfortunately, it appears that SERIF programs are for Windows only. If you want to install them, you need to try using a program on linux called Wine. It is an implementation of the API layers on windows (fancy talk for you might be able to make it work). You may be able to find equivalent programs. For example, it looks like Page Plus is similar to Scribus
in Linux. PhotoPlus appears to be photo editing (the linux equivalent is the GIMP
Most linux distros will allow you to install programs from one central repository. I don't use Mandriva, so I'm not sure where to look for packages for these programs, but the link in #1 shows how to install them and several other programs. I'd read through it and see what things you think you might want to install. Of course, you'll have to learn how to use the new programs just because they are different than what you may be used to. But there's some really quality software as you have probably seen.
If you have any other questions, don't hesitate to post a new thread. Be as specific as you can and that will make it easier for people to help you. Enjoy, and welcome to linux!