I have to ask, why not ask the doctor to explain it, if you didn't understand? He/she is the best resource.There are a lot of websites that explain Pulmonary Function Testing and the results.
People with CF can have PFT results up to more than 100% of the expected test results. The "expected" numbers are based on your height, weight and age. Your "number" may be "good" or "bad" relative to what your previous results have been. For example, have your PFT results been trending down? Going up? Do they go up and down? Are you currently "sick" with an active infection?
I highly suggest getting and keeping copies of your PFT results.
Google any of the terms below and you will find a lot of info, including what FVC, FEV1, etc., means. The best sites to do general medical information searches are run by government health agencies, medical journals, medical organizations (like the American Lung Association), etc. I'd do the work for you, but you need to start advocating for yourself and learning where to find accurate info. The more info you have, the better you can take care of yourself.
Spirometry
Pulmonary Function Test
PFT results
FVC
FEV1