I'm ( 18 year male , bachelor first year)I saw a girl of my same college while she was going college a month ago, i didn't get the chance to see her face because I was behind her but all i think is about her , she was wearing earbuds at left hair , her dress was iron , her hair was curly ( i find hair seducing) . That was the last time i saw her , until now i didn't get the chance to see her

So i want suggestions, if i saw her again in the future, how should I approach ( she is from same college as me , but her department is different) , i hadn't approached any girls in my lifetime , so I don't know how to talk to girls or how to approach them