Adding single external html file to site

Hi,

I have a wordpress site for a customer who has now entered into a reseller type agreement. As part of the updates required to the site for the agreement, I have been given a html file by the reseller with the following instructions:

“The file needs to be saved to your server from where it can be linked to via your website. Any visitor landing on your website who then clicks on the link will be taken to your branded reseller site.”

I am really struggling to link to the file! I’ve looked through various forms and have so far uploaded via ftp to the public and theme directories, plus have also tried creating it’s own named directory in public too.

Where am I going wrong? How to I get this file to appear on a custom menu link to redirect visitors to the branded reseller site?! I know this is something obvious so definitely feeling the frustration today lol!

Thanks in advance