Learn Farsi: به نظر می‌رسد که این معبد مهم است.

While English speakers sometimes associate "seeming" with uncertainty, Farsi treats به نظر می‌رسد (it seems) as a verb of perceiving or stating an observation. Verbs of perception, thought, or declaration generally introduce statements of fact, so the following clause uses the standard indicative mood (است) rather than the subjunctive.

How does the phrase به نظر می‌رسد literally work to mean "it seems"?

It translates literally as "it arrives to view" or "it arrives to opinion." The word نظر means "view" or "opinion," and می‌رسد is the third-person singular present form of رسیدن (to arrive). Farsi relies on this impersonal structure where English uses "it seems."

Where is the Farsi word for "it" in this sentence?

Farsi does not use "dummy subjects" like the English word "it" in phrases like "it seems" or "it is raining." The third-person singular verb می‌رسد acts on its own without a separate subject pronoun to carry the impersonal meaning.

How would I modify this sentence to say "It seems to me that..."?

You would attach the first-person singular possessive enclitic ـَم directly to the noun نظر. This makes the phrase به نظرم می‌رسد (literally: it arrives to my view).