So you start a New Game and end up in the level that started it all: Negotiations. The cutscene should look familiar if you played LEGO Star Wars. So you're in a room with a table and chairs. First thing you have to do (after testing the controls and breaking canisters) is use the Force with the Action Button to break down the door. Security Droids will come at you. They will shout "Intruder Alert", which the subtitles will confirm (a rare case of dialogue in the Star Wars levels. Defeat the droids and run down the hall. Ignore the doors on the side, as they are for Free Play. Even the originally unlocked door at right of the start has a Nazi guard. After defeating Battle Droids and reaching the end of the hall, you will meet TC-14. Get close to her and the Tag Button will flash. Press the Tag Button to switch to her, which will add her to the Character Wheel and if you are playing the Wii U version, the Character GamePad. Use TC-14 to access the Protocol panel to open the door. Switch to a Jedi and walk to the end of the corridor and use the Force to open a grate so that pieces would fall out. Build them into a Protocol panel. As you may notice, the Jedi don't stack pieces anymore. They use the Force to create a whirlwind that stacks the pieces. After that use of the Force, switch to TC-14 and use the Protocol panel to open the door. Switch back to a Jedi and force a big grate, revealing a couple of Template:Charforms waiting. Defeat the droids and get in the hole.
You have reached a Checkpoint. Notice a computer right under you? That's a Save Point. Drop down and press the Action Button to access it and select "Save and Continue". The computer will withdraw into the floor and the marching Battle Droids will shoot at you. Defeat the droids. Go down the steps and defeat more droids. Two Droidekas will show up. You can weaken their shields with slashing and deflecting, but a faster way of disabling them is to do a double-jump slam. Destroy them when their shields are down. Use the Force on the panels on the side of the force field to create platforms. Jump over the force fields and step on the buttons to let TC-14 through. You will be ambushed by more Battle Droids. Destroy them all, and use TC-14 to open the MTT. Get inside for the ending cutscene. You've completed the first level in the game. Watch as you unlock stuff. At the end of all of that, you'll get one option: Central. Click on it and move on.