User behavior in Google analytics by custom user id
Hi, I am new to Google Analytics and I have some problems about implementing customer id.
The project is for a WeChat official website, user could browser this website after login. However, I can't pass the user-id from WeChat into Google Analytics environment, so that I can't use Google Tag Manager for Google Analytics.
Here is my questions:
1. Can I use the tradition method to pass custom user id?
2. How to implement?
3. Our developer only can pass the user id as an Event.
4. Can I track user behaviour per custom user id?