1. How do I place objectives and how can i get an enimie to get involved?
Read the manual.
2. How do I make explodable walls?
Search scripts forum/models and media. Or... use a wall mesh, and copy the crate debris meshes to the smae folder
3. How can I make it so that others can play multiplayer?
By changing the preferences in the file menu. Probably not possible in demo
4. How can I make a second level?
By closing your first level, and starting a new map. If you mean, make a second floor above the first : read the manual
5. How can I change what story spots do? Instead of just showing your guy walking forward?
Right click the storyZONE and go to the bottom of the menu that appears on the right. you can change what video plays (you'll have to make your own...tutorial on that in tutorial city)
6. What are trigger spots used for?
Well, they're like trigger stripes, but spottier. SEARCH the scripts forum, theres a FULL COLOUR tutorial with pictures right there! Supagamer posted it about 3 days ago!