As per VR arcade game teaches teenagers to live on another planet, children doing VR training for exploration of a planet, only to find they've actually been dropped there is likely Invitation to the Game by Monica Hughes.
They come to realize that The Game was a kind of training program meant to prepare their group, and others like them, for an off-world colonizing project – a project designed to halt the massive overpopulation their world is suffering. The different start of this phase of The Game, which they thought was a new level, was in fact their transportation to the new world, where they have been left forever. Lisse starts to remember them landing in an egg-like structure. They retrace their steps and rediscover the landing site – this confirms that they have been transported, and that their memories had been tampered with. Eventually, they christen the new world "Prize" – ironically at first – as their new life there is what they have won in The Game.
It is hinted that part of the reason such a group of people were unemployable out of school was to help in the colonization of other worlds, since each seed group would need a variety of talents. Indeed, an early portion of the book reinforces this supposition, as it explains that the prestigious school from which Lisse and her friends graduated once had a 90% job-placement rate, which is now a mere 10% – possibly suggesting that the most qualified graduates are being placed within the Game system rather than the workforce.
Lisse and her group encounter and integrate with another group; they all eventually pair off into relationships. Lisse explains that her original group could not intermarry as they are too close and feel like family. The book ends with Lisse making paper to write a story to the unborn baby she is revealed to be carrying, which she thinks will be a girl – the first child born on Prize.