In this tutorial, you'll see two ways to link Huawei Health with other fitness apps.
On your phone, go to Huawei Health, then go to "Me" section. Swipe to the bottom and then click on Privacy Management, once you're in the Privacy management page, click on Data sharing and authorization, you can see the available apps to link your data (it's very limited...).
As you can see in the first method, the link via the Huawei Health app is every limited (as their watches :D ), fortunately there is another way, you will just need to install an app named Health Sync, once you've installed it, open it and follow the instructions.
Tip : Health Sync isn't free, it offers a 7-day free trial, if you want to 'increase' this trial, you can erase the app's data every week, but you need to setup it again each time.