Need help fixing website rescaling and video playback $30

Fix HTML5 code to scale proportionately the video background of a one page site when the browser resize (original code generated from Adobe Muse).

Suggest and Add code to load and play only once an audio file on page load.

Fix code to replace Contact Form from Above Muse widget. It uses PHP not supported by hosting site and must be replaced with https://formspree.io/ code or other solution, while keeping design and style.

Must supply documentation of the changes applied in order to port them on further versions. Fix video in the background not playing on iphone/ipad in some countries.