"Please put those files into a folder."
Translation:Bonvolu meti tiujn dosierojn en dosierujon.
It has to do with movement to a certain place. Since the folders are being put into the folder, i.e. moving towards the folder, the folder gets the -n.
Like when we say "Mi iros tien." It means, "I'm going there (towards that place there)."
In the same way, the files are going "there, towards that folder (and into it)"
but "dosierujo" is an object of a preposition, and I thought objects of a proposition did not get the "n", just direct objects
marking the direct object is ONE function of the n-ending, and it happens to be the "main" function as in it is the most common function.
there are other uses, such as 1) indicating a quantity, 2) direction/motion, 3) a point in time, and 4) sometimes it substitutes a preposition entirely.
in the sentence in question, the n-ending in dosierujon relates to direction, and is indicating that you're putting the files INTO the folder. picture this n-ending like an arrow pointing into the object it's attached to, i.e. the folder in this case.
everything you will ever need to know about this is here (in Esperanto): http://bertilow.com/pmeg/gramatiko/rolmontriloj/n/index.html
you're level 14 so make us proud and work through it if you're not used to reading in Esperanto! :)
of course, you can ask for clarification if you need to.
In particular, in this case the -n on dosierujon is actually both "direction/motion" and "substituting a preposition entirely". To write it without the preposition we would need to say "... meti tiujn dosierojn al en dosierujo". The -N ending is actually replacing "al" in the sentence. We are moving the files from outside of the folder to inside of the folder (indicating direction/movement). If we dropped the -N we would be indicating that we want to put the files in a different position within the folder they are already in.
Can you not say "bonvolu metu"? (I can see why you might not, but wanted to check)
Yes because only one verb can be conjugated in the sentence, the verb next to it must be an infinitive.
I guess the confusion comes from not really seeing "bonvolu" as a verb in the sentence, it kind of stands on its own. Would adding a comma make this correct? "Bonvolu, metu tiujn dosierojn en dosierujon."
I dont think so.
Bonvolu is "please" as in "please do this" or "i politely wish you to do this"
If you put metu in the imperative like that then you must either drop bonvolu or change it to an adverb like "bonvole metu" meaning "kindly put"