Inventor Level 1 comes with a single palette of programming tools.
These can be used to create simple programs involving motors and lamps for output, timers and the touch sensor for input.
Make sure you can see the Tools palette (Window/Show Tools Palette). Use the Arrow tool to select and move items.
As a first step, remove all the existing icons except the green and red traffic lights (start and stop) and the wires as well. To remove an item click on it with the arrow and press the Delete key on the keyboard.
To develop a program click on the icon in the functions panel (use Window/Block Diagram if it is not visible) and click in the main program window.
The best way to place a new icon is to drag it from the Functions palette to the program window and place it close to the previous icon so that the pink wires appear and it is linked automatically.
If you place icons without linking them you will have to use the wire tool to do so. To link the icons with 'wire' and make a working program choose the wire tool from the Tools palette and join the icons in the block diagram together in their top right and top left corners.
Program 1: Turn on motors A and C for ever:
In Inventor you must add a stop button, the motors will not stop when the program stops, only when the RCX is turned off.
Program 2: Turn on motors A and C for 2 seconds and then stop them:
Program 3: Turn on motors A and C until the touch sensor is pressed:
Note that the touch sensor has two states, it can trigger an event on a push or a release of its button.
You can certainly create simple traffic lights at this level and a number of other simple models as well. You should be able to make a buggy (with touch sensor) detect a obstacle in front of it and take action such as reversing and turning. Another action might be to detect an obstacle and push it for a short distance before turning back to find more obstacles. The turning back operation might involve a buggy moving around inside a small circle looking for objects to push.
Another application would be to write a sequence of steps for a suitably 'designed' buggy to make it 'dance'.