Hi
Just like Dave R said, you need to undo the nuts at the other end of axle and slide it out. The cone and locknut at the gear end stay on the axle unless they need replacing. Just check the 'fixed' nuts are tight against each other.
You have dismantled the freewheel which isn't normally done due to the small bearings and risk of losing them or the pawl/ratchet springs. However, all is not lost and they can be rebuilt with care, used to do it all the time when I was a teenager. Just use a small amount of thin grease to keep the bearings in situ during re-assembly.