Static Page problem

I cannot get the static page option in “reading options” to work. Whenever select it, the pages I’ve selected don’t work at all, and the latest post shows up on both the “static”ages I’ve selected. Very frustrating !
I have searched the forum – some answers I dont understand, while one answer suggested choosing only a ‘front page’ and not choosing a ‘posts page’. However. my version doesnt give me the option – I have to select both.
Any not to technical suggestions, ideas etc would be very welcome ??