Setting up your manuscript repository

Go to your preferred folder, where you're planning to keep your manuscript file. Now, follow these steps:

Creating and cloning repo

Create a github repo by gh repo create username/repo-name --private here the username is your github user name and repo-name is the name you want to give your repo. --private tag ensures that the repo can be accessed only by you or by the persons who you invite.
then clone the repo to your local machine by gh repo clone username/repo-name
you may get a warning that you cloned an empty directory - you can safely ignore it, because hereafter only you're going to add the files

now open VS Code and the File > Open Folder ... Navigate to the repo-name and open it
In the Explorer tab, click the New File icon and create a file manuscript.tex
Double click the file to open on the right side editor
this is our manuscript file and here is we are going to write our manuscript

aaaaaaaaaaaaaaaaaaaaaaa

save it
now you can see a number badge on the left panel, source control
click that icon, you could see a message box, followed by commit button and a list of changes
in the message box type a readable message like files initiated and click commit
the message is crucial, because if you want to switch back to particular version later you can directly read the commit message and switch to it. If you use same message for different commits it would be hard to locate you version of interest
now click the Sync option to sync with github account. if you open your github repository in the browser you should see the updated file.

even without VS Code, you can commit and sync with github (however gh-cli is essential to clone and push)
to do that, first add the files to git tracking by git add . this will add all the files
then commit it by git commit -m 'files initiated
finally, sync to github by git push origin main or simply git push

when compiling the tex file it would produce log files and auxilary files. which you often no required to sync with the cloud.
you can safely ignore these files by creating a .gitignore file.
click add a new file and name it as .gitignore - note the . prior to the name
open the file and add the extension of files you wish to exclude from sync

# the following files has to be ignored

.log
.aux

you can first create a file and folder, than it can also be added to github
for that make sure you have git and github-cli -- create a repository using gh
then in your local folder, initiate git by git init
then follow add and commit the files
now, add your local directory to the github by git remote add origin REMOTE-URL
check it is properly configured by git remote -v
then sync by the command git push or git push origin main