Two boys stood in front of me.

Literal

I [of-の] before [at-に] 2 [counter-人] [of-の] boys [subject-が] stood.

Number+counter (二人) precedes the noun via の, acting like a prenominal modifier — the alternative to the floating quantifier pattern. 人 is the counter for people. The に marks the location of standing (position of existence), not motion into place.