by Knightmare » Fri Jan 04, 2019 6:04 pm
That tutorial link is now dead, and it looks like the Internet Archive's crawler never managed to grab it.
For adding a key to use an object, I'd recommend looking at the source of the Lazarus mod (included with the KMQuake2 source and also downloadable ). It implements a bindable "+use" key for activating various new entities, such as pushable crates and security monitors.
BTW, you should never hardcode a single key to a function in an id tech game, as some players will want to use that key for other purposes!