if you manually installed it, you found your old saves under <user>/<username>/appdata/locallow/denki/autonaouts as txt files.
if you use the itch app it maybe saved under <user>/<username>/appdata/roaming/itch/apps/autonauts as txt files.
as a side note the folder appdata is a hidden system folder, you may need to un-hide it or just use the path box and write it manually in to gain access.
