There are several really important (and lots more moderately important) things you have very little chance of understanding from the official docs alone. Read Jim Aikin’s Inform 7 Handbook. Bookmark a keyword search of IntFiction’s I7 category and use it liberally. Bookmark the I7 Documentation and Resources post. Read the linked-to Useful posts and threads, especially this: most common mistakes for those starting out with I7.
Use the Project Index, which provides a reference to many things you might have expected to be in the documentation.
The docs don’t attempt to convey all of the details of Inform’s default world model. Look to the Standard Rules themselves (that’s the 9.3/6M62 version, but the parts regarding actions are close to unchanged in v10.) and to @OtisTDog’s Standard Rules reference.
Ask for help. Don’t be shy: that thing you’re banging your head against and can’t figure out? It might be one of the things I referred to where there’s no real chance of getting it from the docs. Learn how to ask productive questions, i.e., ones that make it easy for other people to understand what it is you’re after so they can give you a relevant answer. (I had originally said “good” question there, but I changed it so it didn’t sound like some value judgement.) In particular, if some bit of code behavior is stumping you, work at boiling your code down to the simplest, most straightforward example that demonstrates whatever it is that’s vexing you. This’ll tend to be something like the shortest example too, but simple and straightforward are the more important goals. Use a code block to post it – you get one either with the </> icon above the edit box or by putting a line of 3 backticks: ``` above and below it – and copy-paste your example directly into it, so that tabs are preserved and other people will be able to copy it with the copy-to-clipboard icon that appears in the upper right of such code blocks.
Lab is a room.
(You’ll also often find it the case that you’ll solve your own problem during the process of boiling the problem down.)