Once you have installed Linux rebooting your machine will let you know if everything is installed properly. If when you reboot your machine all that happens is that windows boots straight up is that the chances are you havn?t installed the boot loader (lilo) properly, if this happens you will need to boot to linux using the boot floppy disk you created at installation. Once you have accessed your system you can install lilo from there. This can be done in a number of ways depending on your distribution but will normally involve you typing lilo in the console.
If lilo does boot straight and you get a list of operating systems move down to Linux if its not already selected and press enter. This will then boot your system, don?t be alarmed when lots of writing scrolls up your screen ? this is normal and as long as everything says [ OK ] by it you are fine. If something does come up in red then don?t be alarmed it may be something simple like it can?t log onto your network which unless you need a network will not effect the way your pc runs.
Once Linux has runs through its boot up procedure it will probably ask you to login. You should have set your login information in the installation process. I suggest you login with your account rather then as the root encase you do anything you shouldn?t have thus causing errors. If you have a graphical login screen you can normally choose whether to enter into KDE or Gnome, if you are at a console screen type KDM or GDM to enter the K desktop manager or the G desktop manager.
Once your GUI has loaded you will notice similar things to windows such as the desktop and similar start menu and icons. Take a look around and try some of the different programs, you may have some fun. If any errors do come up I suggest you take a look at the distributions website or manual as the chances are if you have an error someone else might have had it before.