Others have felt your pain.
How Do I Clean My Typewriter?
Check out cleaning tips in Typewriter Cleaning and Cleanliness
How do I reattach the drawband?
The concept is similar across many typewriters. Check out some of these videos:
How do I fix a sticky ribbon vibrator?
The most likely cause is gunk in the path where it travels. Flush it a few times with a cleaner. If it moves fine when still wet, spray compressed air in to get all the cleaner out, and repeat a few times.
It is also possible something is bent. Bending things back - called reforming - is something you need to be very delicate with and careful about. Older metal is often brittle, and when it isn't, it's still sometimes easy to crease. Make very tiny adjustments and check if it works each time.
What do I do if letters are getting cut off?
This could be because your ribbon vibrator (the part that raises the ribbon up) is not raising enough OR that you need some adjustment to the shift mechanism. A fix for the former can be easier and should be attempted first. However, before any repairs should be attempted, make sure it is *clean*. Dirt and will also prevent it from raising high enough. On a few machines, an improperly threaded ribbon will also cause this issue.