How to change spark plugs

[mitsua]

I'm somewhat mechanically inclined and I've been doing some research but one thing I came across has been in the back of my mind and making me get cold feet in changing my own spark plugs. Somewhere I read or heard that you have to be hooked up to a computer or something when changing spark plugs. Is this true? I watched a video and the guy didn't do this and his Yaris was a year older than mine (mines a 2007). Is it as as simple as the guy described as changing them one at a time from left to right? I searched the forums here before asking as I had expected someone else may have joined for the same reason as myself, to get technical support, but I didn't find any threads that matched what I'm asking. Thanks in advance for any help! My Yaris has 127K miles now and I'm getting the coolant replaced at a shop only because I want it flushed. I'm also thinking the back brakes need replaced, my car has been doing some weird squeek when I let off the brakes but not as I'm applying them. I read somewhere online that others who experienced this found that cleaning and/or changing the rear drums fixed the issue. I figure its probably been long enough that they should be replaced. My uncle owns a car shop and said that after that many miles even if the brakes look good you should have them replaced because the brake material gets weathered from the heat. I asked a guy at a different shop and he said they only recommend replacing them if they actually need it and that brakes nowadays can last. I only questioned why my uncle was telling me because his quote to replace the coolant was more than having it done at the dealership!...as was the rest of the work