You're close, but a couple of the constructions aren't grammatical.
"The descriptive book machine is ready, it is time to use the link."
I'm replacing "use the link" with the verb "link", since a noun form of "link" isn't known, and neither is a multipurpose "use". Also, our understanding of how to form open compounds like "descriptive book machine" is a little sketchy, so kormahn doyhah may be reasonable, or you could try a safer combination like doyhah kormahnselahl "descriptive-book-writing machine". All together, that's:
.reh kormahn doyhah kenen ahtsoo .kenen gor b'baykh OR .reh doyhah kormahnselahl kenen ahtsoo .kenen gor b'baykh
Let me know if you want help transcribing into d'ni letters - I can also provide a Dnifont- or D'ni Script-mapped version.
That should be .rekormahn doyhah kenen ahtsoo .kenen gor b'baykh OR .redoyhah kormahnselahl kenen ahtsoo .kenen gor b'baykh That is, the "re-" should be attached to the noun.
Yet another way of saying "the descriptive book machine" is "redoyhah tso kormahntee": "the machine of descriptive books". It is more long-winded but more attested.
I did forget to reattach the re- to doyhah in the second option, but only because it's left separate in the first for a good reason: since the head noun is doyhah, not kormahn, it doesn't strictly make sense to attach re and kormahn. Rather, re is the article for the whole phrase, so I borrowed the rule that okh seems to use in these cases and left it separate. (Furthermore, there is at least one case where re is left unattached even under normal circumstances, so it doesn't necessarily latch on to the nearest word.)
As for a prepositional phrase involving tso, I didn't like suggesting it because A tso B seems to only be used when B is the recipient of an action that A specifically entails. You could argue that in context, there's only one possible way the machine could be acting on the descriptive books, but I tend to think it's more of a syntactic rule than a semantic one. I'd be happier using okh in place of tso, but that may be mostly because okh seems to be a catch-all for the "of"s I don't know what to do with, so I didn't suggest a prepositional phrase at all.
In the end, what we know about d'ni is so small limited that there often remain many choices consistent with what we know about it, and ranking those choices by how well they match the existing examples can be a rather subjective process.