Why don’t you just hire an electrician first.
An electrician is your friend here. You need to do it right or you could be flirting with big trouble. Always remember to shut off your main breaker before starting your generator. Otherwise you risk hurting or killing a utility worker down the line.
I was advised to get everything that I need first otherwise the electrician might either A) over charge me if they have to procure the parts, or B) have to make multiple trips to my house due to not having on hand what he needs to complete the job.
I avoid calling any repair people. Their price tags are waaay too high. I do it myself, and if I don’t know, I watch video tutorials. Plus I like the challenge.