Hi Funkmaat, welcome back to Subsim
To be able to freely turn on/off your TDC via the WO officer window in the periscope or UZO view, you must go in the OFEV (Option File Editor Viewer) , go in the XOTDC tab and change the last option to 'false'. All this assumes you are using the TWoS mod or at least the TDW NewUIs 7_5_0 mod.
Then, you must set in your Game Options accordingly what type of TDC you are using, if you play campaign you must set it while in the bunker, for single missions you must go to Game Options in the main menu.
The tutorials you speak about are automated scripts included as single missions or scripts you can run during campaign when you install TWoS or TDW NewUIs 7_x_x, without these mods you cannot run these scripts and there will be no such specific single missions added.
To start such a script, go in the NavMap, select the 'Automation' icon on the right, place the script you want to run so that it appears in red to the right side of the window, select it, click the left lower tab in the window. You can now toggle start/pause the script at any time with the 'X' key or by commanding the script window. Same procedure for all scripts and Harbor Pilots.