First of all Fork the repo.
Then type the following command on the terminal to clone the repo keeping in mind to replace the {your-user-name}
with your github user name.
git clone https://github.com/{your-user-name}/voice-controlled-departmental-noticeboard
Now you need to move to the project directory.
cd voice-controlled-departmental-noticeboard
Change or add the things what you think can make the app better.
First of all you need to check if there are any new commts in the main repo or in other words that your repo is behind the main repo.
Click on the Fetch upstream
drop down button.
and click on the Fetch and merge
button.
The repo will be up-to-date with the main branch.
Add files to the staging area in git with the following command
git add .
Here . means that you are adding all the files that you added or updated.
In case you want any specific file you can write the name of the file like git add {filename}
Now commit the changes you put in the staging area by following command.
git commit -m "Some useful message about the changes"
Now push the changes to the github repo (It will be your repo which is forked.) by the following command
git push
Now simply open up repo and click on Contribute
and create a pull request.