Unless you have a ton of money, I doubt paying somebody to design your office space will be worth it. Plenty of other more important things to focus on at this stage.

Just make sure everybody has a comfortable chair, a desk (standing desk if you really want), some tables and chairs separate from desks for meetings, etc. If you've worked in offices before, most of this should be common sense. I wouldn't worry about office design until you've grown enough to need a large office of your own.