This Seeking Tech guide will explain how you can get to the rooftop of the Changing Room building in Astro Bot.
Use the following video as a reference:
For the first step, make sure you beat the five main galaxies in the main campaign. This should let you climb all the way up the PS5 system in the Crash Site hub.
Next, you need to climb the construction section until you get to the jumping pad. You should then turn your camera towards the Dual Speeder Garage building, which is the one that looks like a paint bucket.
Once you are ready, bounce on the jumping pad and then hover directly towards the bucket. You may need to do a spin attack at the end to get there.
You should then be able to jump and hover to the Changing Room building.