Uploading to a website is done using a program called an 'FTP Client'.
We recommend a client called 'FileZilla', it is a free download and offers many features without any spyware or adware
You can download from here: http://filezilla.sourceforge.net/
You can also see the installation instructions which show you how to use FileZilla here: https://milliondollarscript.com/installation/documentation/docs (Step 3).
Please refer to your web hosting manual to find out which directory to upload the files to. On some hosting accounts, you will need to upload the files to a folder called 'public_html' or 'www'. You may wish to upload to a subfolder named pixels or something similar to separate it from other files on your site.