If you want to use a verb after ‘before’, ‘after’ or ‘without’ it must be in the gerund form (ing) and not in infinitive. Thus, to say ‘antes de ir al evento necesito comer’ would be ‘before going to the event, I need to eat’. Definately don’t say ‘before to go…’. Similarly, we’d say ‘without/after going to the event…’. Hope that helps. Have a great day.