First Day Of Work?

so today is my first day workin at tim hortons and i was wondering how early i should show up, and if its ok if i wear sandals there and then change into shoes... because its pretty hot out and im wearing pants and a shirt so i dont wanna get sweaty b4 i show up and what not. also is it ok if i wear brown dress pants and a brown and white striped shirt there? i know they give uniforms but i dont wanna look informal. ALSO should i wear my hair up right away?