Hi Norma,
What age are your students? If they are school age - it may be more reasonable for them to take Preliminary for Schools because of the scope of vocabulary (it does not entail issues related to work/career, professional life, which makes perfect sense in their case, instead there are questions about school, there is no indication of the type of exam on the certificate).
There are 4 parts to the Listening test, Reading and Writing are one test (and comprise of 5 reading chunks and 2 writing ones), the Speaking test has 4 Parts. I understand you need sample tests? You can download them on the official website here:
for Schools version website with the wordlist:
regular Preliminary website with the worlist:
And here is a sample speaking test video so that your students can get familiarized with the format:
You can also browse through one of my worksheets which contains all transformations for PET if you like :-) If you have any questions, I �ll be glad to help.
best, joanna