The model tree is located on the left hand side of the window. This is the main place to find all the tools to create boundary conditions, loads, sets, materials etc.
The Command Line Interface is located at the bottom of the window and shows recent activity that you have performed.
The menus available in the top toolbar will change depending on the Module you have selected. The Module can be changed by selecting from the dropdown list 
.
The module will change automatically when you select different tasks from the Model tree. For example, when you want to apply a load by double clicking Loads 
in the model tree, it will automatically switch to the Load Module.
The Module tools, located to the right of the model tree will also change depending on the Module selected.
Pan: Ctrl + Alt + Middle mouse button (MMB)
Rotate: Ctrl + Alt + Left mouse button (LMB)
Zoom: Mouse wheel
Select: LMB
Add to selection: Shift + LMB
Deselect: Ctrl + LMB
Change rotation centre: Click 
in the toolbar, then click Select in task bar 
Change the Perspective: 
Change the background colour : View > Graphics Options... In Graphics Options you can also change the Drag mode to wireframe for faster movement.
Take a screen capture: File > Print, in settings - select File, Browse files, select format and choose the image size by clicking 
.
Set working directory: You may want to change the working directory (the default is C:\Temp), File > Set work directory...
To change the element type (linear to quadratic): In the Mesh Module, select the menu Mesh > Element Type... then select the region to be assigned. In the dialog box that appears, change the Geometric Order (Linear or Quadratic). Linear are 4-node tetrahedral elements (C3D4) and quadratic are 10-node tetrahedral elements (C3D10). Quadratic elements are more accurate but take a lot longer to solve. 4-node tetrahedral elements are standard from Avizo and do the job if you have enough of them.