Once you're in Huawei Health, you'll be prompted to sign in with your Huawei ID (which you'll need to create if you don't already have), although you can sign in via SMS to save time. This should take a short while, but when it's done, the Huawei Mobile Services you downloaded before should be updated, which means you can head into Huawei Health without any issue.
When you're in the AppGallery app, agree to its permissions, then search 'HMS Core' and update it. Now go into your phone's downloads file and select the app, which prompts AppGallery to install. Click 'Install Now', give your web browser permission to download files if you haven't already, and download the file. To download the AppGallery, you have to head over to Huawei's website. The app, which Huawei created to replace the Play Store on its phones (given the Huawei ban means the company can't use the Play Store), is exactly what its name suggests – an app to download other apps with. This third app, Huawei AppGallery, isn't actually available on the Play Store.
