go to your phone and go to...
real estate --> purchase community lot (or something)
then it is yours. get in a taxi to go to it.

*all you have to do is go to either your phone or computer
*click phone/computer and click on REAL ESTATE, then PURCHASE COMMUNITY LOT, or whatever
it says.
*then, once you have purchased a lot, you need to get to the lot, lay out your store, make
sure you have all the needed objects in order to start the business (such as an
open/closed sign, cash register, etc.), then make sure you have the employee spots filled
with a family member, or an employee, and open your business. It is actually very easy.

If you need an example on what to make the business look like, simply just go to youtube,
search for designer's walkthrough for this game (sims 2 open for business) and watch the
video.