I have talked about the seven sentence patterns here. Those are all simple sentences. A simple sentence contains a single verb, that is, one clause. Complex sentences contain more than one verb, or two or more clauses.
An SVO sentence theoretically can have three clauses, having one each for the subject, verb and object. It is possible to have more clauses (and/or phrases) by adding optional elements like adjectives and adverbs. But the more clauses you add the more complex and difficult it becomes to understand what-is-what within a sentence.
It is advisable not to make add too many clauses to a sentence. If you do find you have created a long and difficult to understand sentence on your hands break it down to two or more shorter simpler sentences.