At the Park entrance one of the turnstiles will have a large sign indicating it is for people with early breakfast reservations. It is staffed both by a person from one of the restaurants and a regular turnstile Greeter. You give your name to the person and they check you off on the list; then you use your tickets as normal to go through that turnstile.
At the Studio, if you come in after we have opened the turnstiles and before the 9:00 rope drop, we have a second check point at the end of the first store building to allow people over to the Hollywood and Vine podium.