When you start Softimage for the first time, you are prompted to choose an interaction model for mouse and keyboard actions. You can change the interaction model at any time.
The different interaction model set a variety of preferences, including which parameters are keyed by default. It is strongly recommended that you do not switch between models while working because you might not actually be keying the parameters that you think you are keying.
For more information, see Selecting Which Keying Method to Use [Animation].
It is recommended that you choose the Softimage interaction model because it is optimized for use with all Softimage tools. In particular, it makes the most efficient use of modifier keys like Shift, Ctrl, and Alt.
If you prefer to use the Alt key for camera navigation, you can set Use Alt key for view navigation in your ToolsCamera preferences (File Preferences). You can also set Mouse Mapping to Maya to use the left mouse button to orbit, the middle mouse button to pan, and the right mouse button to zoom.
If you are familiar with SOFTIMAGE|3D, you may be more comfortable either Softimage with Extended Component Selection or SI|3D. Both of these interaction models mimic the selection methods used in SOFTIMAGE|3D. Other users will probably not find these models intuitive.
If you are familiar with Maya, you may be more comfortable with the Maya interaction model.
In addition to or instead of the Maya interaction model, you may want to try the Autodesk 3ds Max-compatible key map. This is not a full interaction model, but a key map you can use with any interaction model. To select it, choose File Keyboard Mapping and then set Key Map to Autodesk 3ds Max Compatible Key Map.