Ok, this may sound complicated at first because roblox doesn’t DIRECTLY support that.
First, you go to the roblox creator dashboard, and select your experience. Then, you go into the experience, and select “Places” under “Configure”. In there, it’ll contain all the places your experience has. Click on the place that you want to get the old stuff back (eg. an area), and click “Version History” (on the panel to the left of your screen) Then, you find the version that contains the area that you accidentally deleted, then click “Restore”. This will restore your game back to the time when the area was still present. Then, you select every object you want to bring back, and save it to your downloads, or anywhere you want. Then, you go back to the version history, and go to the version BEFORE you reverted it back to the previous update. Finally, you once again click “Restore”, which will bring you back to the version you’re currently on, and upload the area that you accidentally deleted into the workspace.
Hope this helps!