How to page query

Hi there I am very new to all this so forgive me for asking a basic question.

I have a query:

cat=4&posts_per_page=1

I’d like to add a paging to this EG first, back, next, last – I tried it with the regular next_posts_link but it just brings up the same post again and again – I guess it’s not as simple as that.

If anyone could help I’d much appreciate it,

Ta,

Caroline