L.A.
In their minds, the world revolves around them so give them items to looks forward to on their new adventures, new friends, crafts, what will they love to do while you are away. Also, reassuring them that you will be back.
The best advice I can give is find a routine and stick to it. Kids love routine it gives them security. Any time I move from the routine there are consequences. For example, I'm on a medical leave and was looking forward to lazy mornings and breakfast with my daughter before I took her to day care (so I can heal). She has not adapted well to this change because if we eat together it usually means that she doesn't have school on that day and she gets to spend the day with me. I've found its less disrupting to her to pick her up from school early instead of changing our morning routine.
We also have rituals when I drop her off at school. I prepare her breakfast and before I leave she gives me a big hug so we both have "energy" to have fun during the day. Another mother, blows kisses in her childs hands so they can keep the kisses in their pockets while they are apart.
Best wishes to you!