If I am not mistaken you talked to another team member and some players about the problem in the meantime. I am going to add a few sentences anyway.
The most important property of commands to note is that they can have (or must have) arguments. For example
PLI shows a simple search box for planets.
PLI XK-745c shows the planet information for one specific planet. While there are commands that can be used with and without arguments it is not a fixed rule that every command works like this.
By the way, you don’t have to manually type in every command you want to use. Almost all content of the game is available by clicking links and context buttons in the existing commands. Buffers with commands can be added permanently to the screens.
In case you haven’t seen it yet, there is a chapter about commands in the handbook.