Remove the knob and rosette from the other side of.
Thru spindle too short on door handle.
Once door is open remove old latch and replace.
Mount the handle near the end of the the spindle on the spindle opposite the one that contains the larger flat ie.
It s nice being able to get through your door without too much trouble.
Hold the knob in one hand and insert the other end of the spindle into the square port inside the door lock.
Try and use a big flat screw driver to open the door where the spindle use to go.
The other end of the spindle and opposite knob is threaded so that this knob can screw on to the spindle and subsequently adjust for door thickness.
It seems the original had broken so it actually was too short to fit where it belonged.
One knob is fixed permanently to the spindle by means of a grub screw through the neck of the knob.
I do this most days easiest way to do it is to insert follower bar thats the technical term for the spindle into the door handle and through the latch in the door ensure door handle is.
The one that screws into the larger flat.
Unscrew one handle and remove the spindle.
Remove the rosette off of the spindle.
Take old latch with you as there are numerous different sizes.