General Layout

Difficulty : Easy,
Require : CSS knowledge.

To change the genral layout (change the logo, move the menu on the right, change the background color, etc), yo can either modify directly the last css used (the only one that has a real effect on the site) or modify the DefaultMaster (or one of its parent) the use your own css. If you want to modify the css already in use, think of backing it up before scratching !
This will affect the whole dotlrn software, except the portlets themselves.