Hire a designer/firm near you from the SEGD.
They are trained to do that stuff.
As a graphic designer working for a retailer though, it might seriously be worth your effort to learn to read a floor plan. And a tape measure (not saying you can’t already but it baffles me the number of designers I meet that can’t.) At some point you may want to do interior branding in this space, or a new space, or someone else’s space, and knowing how to interface your art to the dimensions that actually exist in the space is a good thing to know how to do.
A for instance might be your company going to a trade show or Chamber of Commerce event. Creating a booth design means you have to know a little about floor plans and volumetric space. The better paying jobs in graphic design don’t deal with “flat paper” all the time.