How to install core GMS packages on Huawei 7 Plus? I have a Chinese phone and I don't know what to do with that. I have Huawei 7 Plus (Android 7, EMUI 5.1.1 B223).
How to install core GMS packages on it?
There's no legal way to do this. Google only offers Google Play Services for phones that are approved by the Open Handset Alliance. Manufacturers pay money and the phone model has to pass a conformance test suite to be approved.

Some manufacturers cheap out by not paying the fee or passing the conformance test, and then mislead customers by selling the phone as an "Android phone" even though it doesn't have access to most of Android's software ecosystem.

In March this year, Google added an anti-piracy feature to Google Play Services. Even if you obtain it and illegally install it on an uncertified phone, it will block you when you try to add a Google account.