Drop down menu, with editable options

Help would be greatly appreciated, as i am very new to this, and rather stuck...

what I am trying to create is a small spreadsheet that does the following:

has a dropdown menu with a list of staff on
extra staff can be added to this list

when you select a member of staff- it shows their details.
those details can be edited (so if you select the staff from the drop down menu, and it says age: 16- i am trying to make it so when you type 17, it remembers that/changes that on the other page)

I have attached what i have so far. I managed to create the menus, but I am completely lost, at how to make them editable...

Help would be incredibly appreciated!

Thank you!

lily