A Restricted Area is just that; access into the area is restricted (but not prohibited). That means that in order to enter a Restricted Area (like R-3401-A just west of Columbus, IN) you have to make sure it is not in use. You do that by calling the controlling agency, as shown on the frequency tab of the sectional chart, and asking if the restricted area in question is in use or not. Controller jargon for this is "hot" (in use), or "cold" (not in use). According to the FAA’s Office of Chief Counsel (further detail found in a note below), “A clearance is not required to operate VFR through a restricted area when the controlling or using agency, as applicable, has made a determination that the restricted area is “cold”.” So, if the restricted area is "cold" you can fly through it; if it's "hot" then go around. It's as simple as that. The controlling agency (in the case of R-3401-A, Indianapolis Center on frequency 119.55) does not give you specific permission or a clearance to enter the restricted airspace. They just tell you if it's hot or cold; then you act accordingly.