The packing list will tell you how to pack, since it depends on which trip you are on. Overall, we use a 3-bag system:
Camping gear and personal items for camp (gets packed away in the morning and is inaccessible throughout the day),
Small daypack (stays in vehicle and is accessible throughout the day, e.g., extra layers, prescription medications, extra snacks, etc.),
Hydration pack you wear (all things you readily need, right there on your back). We recommend a 2-liter hydration system (e.g., Camelbak) to carry the things needed during the day (water, snacks, lunch, rain gear, extra layer, sunscreen, camera, etc.), and to easily hydrate without stopping.