Operations are purely group driven end game content, also known as raids in games such as World of Warcraft and Guild Wars. They are one of the many endgame goals of SWTOR, progressing through them to obtain endgame gear, rare mounts and items. They can be done with 8 players or 16 players, with 16 players being a little harder than 8. Operations come with three difficulty moves, Story, Veteran and Master (Formerly Nightmare or NiM)
When SWTOR originally launched in December 2011 there were only a handful of operations, now in early 2019 we have a growing number with more coming shortly. A list of all current and future operations can be found below, including instance bosses such as Hive of The Mountain Queen
Terror From Beyond
Scum and Villany
Temple of Sacrifice
Gods From The Machine
Groupfinder Operations (Daily)
These are Operations than can be found on the Group Finder window, under Operations. Every 24 hours a different operation will appear on Group Finder and when you complete an operation through the group finder you gain bonus awards, including credits, CXP and Unassembled Components.
Progression Team/Prog Group
Operations are the endgame, meaning they are some of the hardest content in the game and so they require a committed and stable team in order to complete the highest difficulties, Hardmode and Mastermode A progression team is a team that meets up at the same time, the same day every week to complete operations content in a progression order. Starting with all the story modes, moving onto veteran and then eventually master! This is a good way to get achievements, and to gear up fast. Story modes can most often be completed easily with an open group, however the harder difficulties require more team work and coordination.
Operation bosses drop a different piece of gear for a tier level dependent on its difficulty.
Each difficulty requires the gear you got from the last in order to do them! So it truly is a progression! As you run through the operations you will gain gear to allow you to get better stats, whilst also levelling up your Command. In turn leading to better gear from the Command Box RNG.
Credit for this guide goes to Discord user Saten, or Saten on Darth Malgus for his assistance with Operations and writing the draft of this guide, it would not have been possible without him.