This is by no means a complete list and should not be taken as a legally sound way to do this.
Any liability issues are on you.
Whatever you do at your skill level, it will be half-baked. The real question here is what does your boss intend to do with these once you are done? Because inexperience can lead to all kinds of issues, most importantly with insurance and fire safety.
It may just be he wants a pretty picture, not a practical working model. A lot of graphic install work is done from nothing more than a floor plan and wall elevation maps.
First get a copy of your local fire code. Your state/county should have that online.
You need to know what the walking aisle clearance needs to be. That should pretty much cover ADA requirements too.
You need to know if there is a door clearance requirement (ie no solid or moving structures like doors or gates within so many feet from any entry/egress door.
You need to locate and map all of your fire extinguisher and fire alarm pull locations, any safety stations, light switches and utility access panels and boxes (electrical/HVAC/water, etc.) Don’t block them with desks or cubicle walls
That’s just a start.
Find out the dimensions of the “seats”
Are these desks? cubicles?
If just desks, do a quick search of cubicles to see how much floor square footage = 1 cubicle space and use that sized box to space your seats.
Did they give you the floor plan as a .dxf file or a piece of paper?
You can import .dxf to Illustrator but you have a limited artboard so bring it in at a scale you can work with. 1:10 (or 10%) works really well as you only have to move the decimal point. For example, 235cm becomes 23.5cm, 144” becomes 14.4” etc.
Have a look at CADTools for Illustrator. (HotDoor.com)
You can do simple isometrics with that and it will build walls etc.
You can export from Illustrator to .DXF in a simplified way. (no fills, just lines, best way is to remove all stroke and fill colors so the file looks blank and export that.
If the simple isometric isn’t going to be enough you can possibly have the .dxf rendered in some way, but short of purchasing one of the CAD or 3d programs that includes a render module (extra $$$$,) you aren’t going to be doing that in house.
Your exterior look will not be dimensionally accurate unless you actually go out there and do a survey.
You could cheat and go out, take photos of the facades and map them into illustrator for the exterior.