I don't understand, you received the project charter, so you're not the one who created it? I don't know about your company, but in all the companies I've known and all the companies I've worked for, the project charter is created by the project manager in conjunction with the project sponsor.
In any case, what you need to do is that you need to share the project goals in the project charter with your network engineer. Once he'll read them, he'll tell you what needs to be done.
My advice is don't try to be smart and seem to be a person who knows it all (by asking irrelevant questions that will jeopardize your authority on the project) , share the project goals with your engineer and let him decide what needs to be done. Based on that you can create your WBS, and then your project plan. (the network engineer should also advise you on how much time each and every task will take)