Relative location means to locate a place relative to other landmarks as opposed to locating a place using a coordinate system. DO NOT use regular mapping software. Relative location doesn't care about highways and interstates. Relative location is true distance (as the crow flies).
For example, you could give the relative location of Orlando, FL as being in central Florida, 13 miles southeast of Lake Apopka, FL, 45.4 miles west of Merritt Island, FL. You could also say 14.8 miles northeast of Magic Kingdom, FL and 48.2 miles northwest of Cape Canaveral, FL