Don’t know what to do

So guys i used to be nerdy and an introvert around girls ,but since last year i was making changes to my life now i glowed up ,gained alot of muscle and i learned how to wear clothes that aren’t so nerdy ,so my problem is i dont know how to talk to girls or have the courage to do it .Everyday there is like a minimum of 15 to 20 girls that will make eye contact with me and smile to me but i dont know how to act to that .