Help a brother out to confess

So basically I don’t know how confessions work and I need help confessing to a girl in my school.

From what I observed over some time is that we both show some signs of mutual attraction like sneaking glances at each other, somehow managing to run into each other more often,One more thing is that she changes her hairstyle when our school is over and she stands around staircase where I come down with my friends. In the past she has tried to initiate a conversation but me being a introverted idiot chickens out.

So how should I confess to her guys? Any tips are appreciated