What does signed and numbered mean?

I write the title of prints in pencil
usually on the bottom left of the print

Then I sign the print and in the case of limited editions,
I also number each print in pencil
usually on the bottom right hand corner of the print

The edition size is decided when the first print of an image is made and can not ever be changed thereafter

The numbers run in sequence for example
1/750, 2/750, 3/750......
 and so on to the end of the edition 750/750