Found the 2 oxygen sensors on a 1996 XLT but how is one supposed to reach and change them?

There are actually three oxygen sensors on the 96 Explorer with the 4.0L V6. One in each exhaust header and the third after the catalytic converter. I found it uncomfortable but relatively easy to reach the sensors by sliding under the vehicle from the passenger side. Make sure the exhaust system has cooled down but is still warm (the exhaust pipes expand slightly when they are warm and will make removal of the sensor easier). Be sure to wear safety glasses or goggles as the metal on any exhaust parts tends to flake off at the slightest touch. The key is the special wrench that fits the nut on the sensor. The tool looks like a standard deep socket but is open along the side. The slit on the side of the socket allows the use of a standard 3/8" socket wrench while the cable from the sensor fits through the slit. I paid $6 or $7 at VIP for the tool.