Hiking Apparel Hiking For The First Time: What To Wear And Bring In Summer Day Hiking?

Hiking for the first time: what to wear and bring in summer day hiking? - hiking apparel

I think the walk about five miles. I have not traveled before.
I asked me to wear what to wear and to search.
section of the gymnasium is acceptable as required in the summer heat or special clothing?
any recommendation is appreciated. Thanks