Best practice working with Developers?

What is the best practice to get a SSG page up an running?

Let's assume I would like to hire a developer with the implementation of a static website that is supposed to run on my hosting package.

The developer makes the setup (SSG, ecommerce, CMS, APIS) from a Figma design.

I could make changes with a headless CMS and maybe CSS.

But what if I want to change fundamental things?

Since I don't have a local development environment on my computer. How does this work in practice?