Make contact with resistence ring

[Redrick]

I keep getting told in game that I have to do that but I cannot figure out what I am supposed to do 'exactly'. I know its probably some stupid little thing I'm missing... but what ?

[Amanoob105]

Step one, build the resistance ring room in the avenger (this is likely the step it's asking for).
Personally it's the very first room I make for all it can offer in the early game.

Step two, keep expanding what regions you have contact with until you find the (other) resistance factions.

[megansweden]

Making contact with the resistance is one thing, the Resistance Ring building is another. After your first Guerilla Op, the Resistance Communications research is unlocked and you are made aware that you need to make contact with the Resistance and expand your network. Once you've researched Resistance Comms, you get 3 contacts. Your starting region should be connected to 2 other regions. Each region has further connections out to others. You use Intel to make contact, and have to scan for some days.

I believe it takes 16 contacts to fully contact the globe (which is not necessary, but is possible to do). This is the Resistance Network. To get additional contacts, you need to build the Resistance Comms facility.

The Resistance Ring is a WOTC-only facility that is available from the start of the game (or after the Lost & Abandoned DLC mission if you have it active). It allows you to contact the 3 Factions and hunt down the Chosen, and also gives you the ability to do covert operations that can get you a lot of nice bonuses. You still have to build Resistance Comms to make contact with the general "resistance" and expand your network, though.