Pretty easy diy project, but understand using dealer or mechanic service, too.
Dealer will probably want you to change out all 8, but it is not a requirement to do them as a set.
I find a warm engine makes job a little easier. Definitely spray penetrant oil on threads before removal especially if you live in the rust/snow belt. It takes longer to remove inner fender for access than the actual r&r of a single glow plug. Make sure the new glow plug has high temp anti seize on threads before install to ensure reasonable removal the next time it is done.