I implemented a new single Gen4s Avamar node with 7.0 software and customer gave me the wrong subnet mask

Tomorrow morning I will have to perform the procedure to modify the subnet mask but I've never had to do it as of yet. I'm wondering if there is a simple to follow procedure out there to change this post installation. It's a fresh install so nothing is on it yet. I've been told the process for modifying the network post installation is tedious and time consuming which is why I'm looking for a easy to follow procedure. Or recommendations to either open an SR and have them webex through my machine to do it for me. I'm also considering just kicking the grid since it's a fresh install and that would take just as long and be less of a headache. Please let me know as I'm needing to figure out what method to do before the morning. I did find the attached document in support but it's pretty loaded with various steps that I don't need to do since it's only the subnet that needs to be changed. The last thing I wanted is to spend several hours trying to sift through a document and figuring what steps I do and what I can ignore. Any help would be appreciated.