Depending on which template you went with you’ll have some default menus and widgets here is how to change them.
Under appearance you’ll see an option for menus. You select that and then you can create new menus. I think you can have up to 4 menus, and each one can have different sets of pages on them if you want. Once you have created your menu then you need to select where it will be. Your menu should show up in the drop down for each of the menu locations.
Widgets are like little website apps for wordpress pages. They have a ton of them and you can add as many or as few as you want. Personally I don’t want any widgets so i remove them all. The widgets that are active are on the right and if you want them taken out just drag them to the left into the section with the full list of widget options. To add them do the opposite.