The message
from "Terry W." contains these words:

Can someone please off me advice as to what kind of fixings I need to hold
the strips to the plasterboard wall and what kind of weight i can put on
them.

Personally I wouldn't. You could hang them from the ceiling with wires
into eyes in the joists, or carry the load down to the floor with struts
- but bookshelves and plasterboard don't really mix.

--
Skipweasel
Pay no attention to that man behind the curtain.