Hugo and GitHub Desktop. Stuck with basic conceptions

Hi! I have installed Hugo on my local machine, created a site (C:\Hugo\Sites\mysite) and happily made a theme for it. I can see my website at localhost:1313. So far so good.

Now I have installed GitHub, GitHub Desktop and VSC. I can see two folders in another place C:\Users\Mary\Documents\GitHub and C:\Users\Mary\Documents\HugoVSC. Is it okay? Or they should be inside C:\Hugo\Sites folder?

I want to upload my website to GitHub to make some more changes and follow them. I also want to publish the website later. But here I am stuck.

1.What am I to upload to my repository? All the files from C:\Hugo\Sites\mysite? Or only my theme? And the other files stay only on my local machine?
2. I plan to make another website later. So am I to make a project (not a repository) for my first website? Should I have public or private repository/project if one of my themes is bought from another designer and I have no right to make it public?
3. When I try to “Add an existing repository from my hard drive…” in GitHub Desktop and choose C:\Hugo (or C:\Hugo\Sites\mysite) as a source I get this message “This directory does not appear to be a Git repository”. Is it because the folder is not inside C:\Users\Mary\Documents\GitHub? Should I move some files from one folder to another on my hard drive before adding it to GitHub repository? Or should I make some more settings in GitHub Desktop? Or should I reinstall it in some other way?
4. I can see that other users on GitHub include “static/images” and “content” folders into their Hugo themes repository. Am I to do the same and wait until my repo size is about 1 or 2 GB or should I use some other place (Dropbox or git-lfr.github.com) to store my md files and my images from the very beginning? As for git-lfr, where am I to put it? Inside C:\Hugo or wherever I like? Where can I get a suitable gitignore?

I have perused a lot of tutorials and articles about Hugo and GitHub for the last two weeks but I am afraid there is too much info for a beginner like me to move from the spot and get somewhere. Please help!

Your questions are very generic and beyond the scope of support that we can offer in this forum.

Please have a good look at the Requesting Help guidelines. It offers some links to general web development and learning the basics of Git.

With the above said I will offer a couple of pointers.

Since you have a lot of images you need to either look into hosting them on a third party service and call them in your content files. These images should not be hosted in Git because as you mentioned the repo size will grow and sooner or later you will end up having problems.

Another option would be to generate the site locally and then simply upload it to a service like Netlify that supports deploying a website from a folder without Git. Also Netlify has a more generous free storage plan. Look it up on: https://netlify.com

If you decide to use Git you will need to upload the entire folder of your Hugo project to its remote repository.

Thank you for your kind and prompt answer.

I like the concepts of Hugo and Git very much but I am afraid it was too reckless from my side to hope that I will be able to get a full-fledged website in a month. Surely I have to read some books on Git and on Hugo before. And maybe even to find a tutor or a teacher. Sorry for my generic and naive questions.