Hello from the Wix DevRel Team!
I haven’t spent much time with this particular example, but a brief look at the documentation leads me to believe it should be possible in the same way you would implement Google Analytics, Google Tag Manager, Facebook Pixel, or any other external JS script: By adding the JS snippet provided by TikTok between the tags of your Wix site.
Follow these instructions for setting up your TikTok pixel: https://www.tiktokforbusinesseurope.com/resources/install-tiktok-pixel
And these for adding the inside of the tags for your site:
https://support.wix.com/en/article/embedding-custom-code-to-your-site
You may also need to set up Google Tag Manager and implement it with that (which is how the first link instructs you to do it), but there are also plenty of tutorials out there on how to that as well. I’ve found ones from Analytics Mania pretty helpful in the past:
Hope this helps!
Rob