If there are questions or problems occur, fast help in English and German you get at the Forum of BwPostman:
https://www.boldt-webservice.de/en/forum-en/bwpostman.html
Since version 1.0.1 of BwPostman there is a button Help in the toolbar at the back end, which opens a new browser window with the forum of BwPostman. Furthermore there is a button in the main view of BwPostman to the forum. A click to the button opens a new browser window or browser tab – depending on browser settings – with the forum of BwPostman.
Since version 2.2.0 of BwPostman You find a new button Manual at the toolbar at the back end beneath the button Help, which leads You to the appropriate chapter of the online manual. This button works a bit specific: In example, if You are at the newsletter list or editing a newsletter at the back end and click to this button, You get directly to the chapter for newsletters. For this a new browser tab or browser window opens, depending on the settings of the browser. Also the button to forum now doesn't open imperatively a new browser window, but depending on the settings of the browser a new browser tab or browser window.
Incidentally you everywhere find tooltips (that is, when you move the cursor to the list entry and wait a little while), that may help very fast. Many are really detailed, some will get improvements with the time.