SoloQ

Open up the addon, get a string, paste into the website, and you're now in the queue. The server matchmakes based on criteria: key level ranges, m+ score, mode etc. Also takes into account bloodlust, battle res, no duplicate specs and kick coverage for the "harder" modes, and requirements loosened as you go down the ladder. And then you get matched. The keyholder gets an import script that lets them invite the rest of the party.