All seniors graduating from California high schools who meet the Admissions index (top 9% statewide) will be guaranteed acceptance to one UC campus (Merced). You will simply apply to the campuses you are interested in attending, and if you are not accepted at any of those campuses, the UC system will automatically forward your application to Merced.
I do have data from UCM showing not all ELC eligible HS students were offered spots last year so it is not guaranteed anymore.