To illustrate I’m using a phrase I caught myself using a couple of times, and no I wont go into detail where and why I used it.

The sentence in German:
Mein Bett, auch Spielwiese genannt.

Very difficult isn’t it? Here a word by word translation:
My bed, also play-lawn called/named.

The word Spielwiese is made up out of Spiel, which is play in general and Wiese, which is a lawn, or grassy field. To give you an idea, this is where kids play on some grass, play soccer, to cartwheels and so on, without anything built over it.

Now that is horrible English, so here a translation that might make more sense and still keeps with the same idea of the sentence in German:
My bed, also known as playground.

You could use a different word, like playpen for example, but the idea (context) behind it is that it’s large, so a playground better conveys the idea. And there we are already at one of the caveats. To translate it properly, the context is utterly important. Nuances are lost or wrong ones gained in translation easy and mostly that’s fine, but still should be avoided if possible.

So now we made this step:
Mein Bett, auch Spielwiese genannt.
My bed, also known as playground.

How about turning back? Say we started with the English phrase and want to go back? Will we get the same German sentence? The short answer: No. Here a word by word translation in German:
Mein Bett, auch bekannt als Spielplatz.

Wait what the hell happened here? Why is it now platz, instead of wiese? That is the problem with direct translation, you get different meanings out of most words, as there are no direct translations for most words, or they are substituted with something else.

This is not really good German either, but good enough for most cases. So here is the entire Sequence again:
Mein Bett, auch Spielwiese genannt.
My bed, also known as playground.
Mein Bett, auch bekannt als Spielplatz.

I chose deliberately a simple sentence, with one word that was a bit special and a slightly more interesting way of saying something, to show you already how hard it might be in this case.

Imagine now to add something to it that has specifics, like it’s a space story, or a fantasy one, special words, names, phrasings that are important, foreshadowing for certain things through subtle hints, there is a gigantic can of worms hidden in this.

So if you can’t translate it yourself, find someone who understands your material very well or someone who is an author in the same sort of stories as you are writing. The more complicated or nuanced your writing is, the more importance you should put on this. If it’s only a manual how to push two buttons, sometimes even Google translate get’s it right (enough).