How to set up and push to a second repo on Github

How to set up and push to a second repo on Github

I am a complete newbie in coding. I already have a repo on Github, for my
project. Now I want to create a second project, and would like to commit
it to github as well. I have researched a while and tried a number of
ways, however, I can't seem to get it to work. Also, in the future, if I
do create a second repo on Github, how do I push to the responding heroku
app?
Can someone help, much appreciated.