Congratulations on your new family member! What did you name him/her? :happy:
I'm quite new to the axolotls as well, and yours is much younger and smaller than ours were when we got them, but to me your little one's behaviour sounds quite normal.
We have three axies, and they have all done exactly the same when first brought into the new environment. And also, when we've had to reset the tank a bit and move things around. Hiding, sussing it all out, waiting and making sure it's all ok in there. If the water is fine and s/he is eating, then I wouldn't be too worried. Give the little one a day or two to get adjusted, feed as normal and keep the lights down, as they don't like it too bright. Our tank is against the window and during the daylight hours, I don't turn the tank light on at all but let the natural light do its job. And when the sun turns over to this side of the house, I close the block-out curtains behind the tank to stop if from overheating and to keep the bright light out. They seem to like that and move much more, when the light is dimmer than when the full tank light is on (and even that is not the brightest kind, but needed occationally for the plants, or whe we just want to see them at night time).
You can keep an eye on any stress signals, although I cannot help you much there as I'm not sure if they are the same or as visible as in the adult axies. I hope someone with experience on the littler ones can help you with that. But for now, as everything is new to him/her, I'd give him/her a couple of days to adjust before starting to get worried.
All the best to you both! :happy: