Where do I sign in so that I can access the databases?
You'll want to always start with the Library's home page. From there, in the Search Databases section (bottom), click on the "A- List" to search by title.
Then scroll down to the J's (or click on "J") and click the connect link for JSTOR. If you are off campus, you'll be prompted for your Chapman credentials. From there, everything should work just fine.
Hope that helps!