What is the narrow path/road/gate

This has me worried

I thought we were saved by belief because that was the will of the father mentioned.

Was he talking to the people of the time because the way to salvation wasn’t opened yet due to his works on the cross,

Is this saying salvation is works based but i thought our works were but filthy rags

Is Jesus saying basically everyone who depends on themselves or other religions. The broad way is believing in false religions or doctrines.

Truly i do not understand this and that’s what worries me