If you have to push the code to upstream(github/bitbucket repo) from computer1, it will available there.
we use git push <remote name> <branch name>
You already have remote name : origin so use it
From upstream you need to get that data.
So normal we clone it first, or get add a remote to pull the code.
In your case, instead of git fetch
you need git pull upstream master
,so that the code will be fetch and merged too.
And it shows you don't have proper access to the repo to push as you misplace remote at git push. Even remote is consider as a name here. so use your remote name which is display on git remote -v
Remote has a name ,so use git push origin master to push the code