They are easy to change.
There is a special socket that has a slit down the side so you can put it on the ho2s and the wire does not get in the way.
Can you tell me what the DTC was? There is an acronym that will tell you exactly which 02 sensor is setting the code. (examples s1,s2, s1b2,s1b1, s2b2, s2b1 depending on the ehaust setup. S stands for sensor and b stands for bank. Sensor one is closest to the manifolds while sensor 2 will be after the cat. Bank one is always the drivers side and bank 2 is the passenger side of the exhaust. Hope this helps.
I could explain closed loop and open loop operation of the heated oxygen sensors and how they work as an input in a predictive system but I would probably just confuse you.