To find articles in Summon, do a search, then use the boxes on the left to limit to scholarly publications, journals, and the language English. Click on a result to link to full text for those that have it. For those that say "citation online," click and then use the Find It! button in the database to link to full text.
While databases like JSTOR are all full text, many other databases, like Art Full Text, may only have descriptions of the articles and not the full text itself. Here's how to get to full text when it's not in the database you're searching:
Click on the "Find it!" button
If there is full text in another database, you will either be taken directly to the article, or you will see a link that says "Full text item" which will take you there.
If there is not a link to full text, there will be a link to Interlibrary Loan so that you can request a copy from another library.
To place an interlibrary loan request, you must create an Interlibrary Loan (ILL) account, which you can do by clicking on "Interlibrary Loan" on the library's home page. ILL requests for articles are often filled much quicker than those for books because libraries usually scan the articles, and they are delivered to you online as a pdf.