Generally speaking you only really need to worry about consoles once you've hit 50th level. You can get them from your fleet's store, from doing reputation, from zen store ships, from lockboxes (usually bought off the exchange)
Yeah there are a lot of different sources, depending on which consoles you're talking about. Most T6 ships come with a free console, for example.
The most popular (stackable) ones tend to be the Fleet Spire's Vulnerability Locator consoles (with the mod being your chosen energy type) and the Fleet Research Lab's Restorative Particle Focuser [CtrlX] [EPG] (for "exotic damage" science builds)
Until you get to endgame levels, throw the appropriate energy type boosters (Phaser Relay, AP Mag Regulator, Disruptor Coil, etc) in all the tac slots, and shield and hull boosters in sci and eng slots if you don't have any useful universals, and call it a day.
If you are not in a fleet and are going to use the regular consoles, craft (or buy) the VR mk II consoles ( a few of them) use ONE upgrade on them if you get it to UR, then keep going if not, move to the next one.
Comments
Some missions give them as rewards as well.
The most popular (stackable) ones tend to be the Fleet Spire's Vulnerability Locator consoles (with the mod being your chosen energy type) and the Fleet Research Lab's Restorative Particle Focuser [CtrlX] [EPG] (for "exotic damage" science builds)
Until you get to endgame levels, throw the appropriate energy type boosters (Phaser Relay, AP Mag Regulator, Disruptor Coil, etc) in all the tac slots, and shield and hull boosters in sci and eng slots if you don't have any useful universals, and call it a day.
Delta Quadrant
https://sto.gamepedia.com/Fleet_Research_Lab