First, while outside China get a friend in a country that doesn't censor Tor to create private obsf4 bridge use Debian Server OS:

https://sigvids.gitlab.io/create-tor-private-obfs4-bridges.html

Importantly include: PublishServerDescriptor 0

This means the bridge is private and the Tor Project will not learn about the bridge so it is impossible for an adversary (China government) to find it by requesting bridges.

Install Tor Browser before you enter censored country on recommended Ubuntu OS:

https://www.torproject.org/

Press "configure" and choose Provide a bridge. Then put in obsf4 bridges.

Next install Tails OS on your spare USB stick (need at least 8GB)

https://tails.boum.org/install/index.en.html

Connect to Tor choose hide to my local network that I'm connecting to Tor:

https://tails.boum.org/doc/anonymous_internet/tor/index.en.html

" Currently in Tails, only obfs4 bridges hide that you are using Tor. "

I recommend enabling persistent storage:

https://tails.boum.org/doc/first_steps/persistence/index.en.html

https://www.youtube.com/watch?v=6tSJSXTkJ50

Next, communicate with your friends in Tails OS using Pidgin using Off the record messaging - this video explains how to do so. Spread Tails OS to your friends.

https://www.youtube.com/watch?v=HsSssbs-Sso

Create an XMPP account at jabber.calyxinstitute.org

The IRC defaults in the video have been removed in the latest version of Tails OS.

Things should be setup nicely when you re-enter China. You have dual boot Tails and Ubuntu.

Recommend not using Windows as it can be used to spy on you.

Documentation on OTR messaging:

https://tails.boum.org/doc/anonymous_internet/pidgin/index.en.html