I am 99% sure that my answer is accurate.
1. First, let's (mentally) put that sentence in the usual order:
"A few ways (that) we can link ideas together in a sentence are below."
a. The subject is "A few ways."
b. "(that) we can link ideas together in a sentence" is an adjective clause that explains (modifies) "ways."
c. "are" is NOT a linking verb. It is a full verb. It means something like "to exist."
d. "below" is an adverb.
Here is a dictionary sentence: "He jumped from the window into the moat below."
The dictionary says that "below" in that sentence is an adverb.
As you have probably already guessed, two words are missing [ellipsis]: "He jumped from the window into the moat that was (existed) below."
Dictionary source: The New Oxford American Dictionary (2001).
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