1. Once you get the spray can put it in the delorean and the light will turn green, doc will then test drive it.
2. Get the spray out of the delorean and goto the past stall at the school. Click on the spray and then click on the caveman.
3. Collect the fur of the cave man and give it to trixy.
4. Goto the future stall at the school and press the 3 orange buttons untill the diamon hits the shower, it will then drop on the floor.
5. Collect the diamon and give it to trixy.
6. Go back to doc an click on the picture next to the stew and generator doc will ask if the pic is ok to use, say no and he will get his photo album out.
7. Collect the photo album and take it back to trixy.
8. Look inside the delorean and the light should be green, if it is then put the spray back in an talk to doc so he can go on the final test drive..