For lifeguarding, Sweetwater requires all of its employees to take the lifeguarding course through the company so that ends up being the interview to be a lifeguard. If you are rude and disrespectful during class, the people in the office will be made aware.
For Assistant Manager/Manager, you go in to the sweetwater office and have a sit down with HR. It is very simple and as long as you are logical and understand what it means to be professional you will likely be offered the position