WooCommerce checkout page template customisation

General information for the website: Ecommerce website
Kind of development: Customization of existing website
Description of every page/module: We are currently building a website using the latest version of WordPress, WooCommerce and Avada theme.
Description of requirements/features: We need to update the WooCommerce checkout page template so it reflects the designs provided.

Various elements will have to be moved around the page and some CSS styling is required to ensure the colours, fonts, borders etc match the designs.

We are aware that certain features shown on the design might not be feasible and we expect to be notified of them before the project starts.

On the attached images, you can preview the current desktop design and the expected desktop and mobile designs.
Specific technologies required: WordPress, WooCommerce, Avada Theme
Extra notes: The PSD will be provided before the commencing of the project.

We would prefer the work to be done on a new instance of the site provided by us or the developer.

Upon completion of the work, we would like to receive the template files and CSS changes and apply them ourselves.

The changes should be as future-proof as possible, so they should not directly alter any plugin files, but should be placed inside the child theme.

We intend to modify more WooCommerce pages on our site, so we are looking to establish an ongoing collaboration with the developer.