Hello Thiet,
you can change “Browse by Department” text using below steps
Go to –> appearance –> customizer –> general configuration –> header setting –> there is text field for category box text

If you want to update Facebook & Twitter links on footer icons then follow below steps
Appearance –> Customizer –> General Configuration –> Footer Copyright Setting

We are not understand your 3rd question “– Add a row of new arrival”
please explain 3rd question again,
Thank You