To modify this product you will require a text editor. There are a wide range of softwares out there that will do the trick but we would recommend Sumblime Text or Coda 2.
To publish your website you will need an FTP client which is a software that will allow you to connect to and upload the HTML files to your server. We would recommend using something like FileZilla.
Connect Using FTP
In order to connect to your server using an FTP client you'll need the following information:
Most hosts create an FTP account for you and commonly send out the above details in the welcome email when you sign up for a hosting plan. Others, require you to create an FTP account through your cPanel. If you have never set up an FTP account before, your host should be able to do this for you and answer any questions you may have.
Below is an example of the FileZilla interface: