I have WIX, why do I need a designer?
Why indeed? In reality, you should be able to design, build and maintain your site with no issue on WIX. But in reality, it's a bit like saying, "Here are some paints, here is a canvas, here are the brushes, now paint the masterpiece that you have always wanted." Just because you have easy to use tools and an idea of what you want, doesn't mean you will be able to make a masterpiece. And there should be no shame in that. After all, unless your site is all about what a great WIX website designer you are... designing is not really not your business.
Now, where do I start?
First. Get a WIX account. You dont need to attach your URL and all of that, but if you know enough to do that, follow the set-up steps and get your account in order. Next, upload and organize as much of your digital assets as you can, photos, graphics, pdfs, video or audio files. Next, take a look through the templates. Now, changing templates after a WIX site has been started is not easy. So if you are sure you want to turn this over to a designer, stop right there. Gather your content together, word docs and so on. Now, find your designer. Not that easy, word of-moth and a personal recommendation is best, but WIX has plenty of resources for finding a great WIX design.
Now, go into your WIX account and set up a Web Design account and add their email. You'll be able to watch their progress and add notes and fully collaborate. Once the site is done, it's best to get a few lesson on maintaining and updating your site. If you are ending your relationship with this designer, just turn off their account.