To parse a relative pronoun:

Tell that it is a relative pronoun and explain why it is a relative pronoun.
Tell what its antecedent is and why.
Give the person, number, gender and explain why.
Give its case.

Parse the relative pronouns in the sentence:

A man who is faithfully attached to religion will be upright.

Who is a relative pronoun.
Its antecedent is man.
It is in the nominative case, acting as the subject of the relative clause to the proposition
who is faithfully attached to religion.
As a relative or connective, it joins the subordinate proposition, who is faithfully attached to religion, to the pronoun’s antecedent, man.

Parse the relative pronouns in the sentence:

Cherish true patriotism, whose root is benevolence.

Whose is a relative pronoun.
Its antecedent is patriotism.
Its nominative form is who.
Its possessive is whose.
Its objective form is whom.
It is in the possessive case.
It is used to limit the noun root by denoting possession.
As a relative pronoun, it connects the subordinate proposition, whose root is benevolence, to the pronoun’s antecedent, patriotism.

Parse the relative pronouns in the sentence:

Compassion is an emotion of which we should never be ashamed.

Which is a relative pronoun.
Its antecedent is emotion.
It is in the objective case.
Is used as the object of the proposition of…. ashamed, to the pronoun’s antecedent, emotion.

Parse the relative pronouns in the sentence:

Here is the sofa that he sat upon.

That is a relative pronoun.
Its antecedent is sofa.
It is in the objective case.
It is used as the object of the preposition upon.
As a relative pronoun, it connects the subordinate proposition,that he sat upon, to the pronoun’s antecedent sofa.