How to collect stool samples

Ive had a difference in my bowel movements and have been asked by my doctor to come in for a blood test and collect stool samples. I went to collect  the samples containers today but when  i looked there was no instructions and the doctors will be closed until my appointment so i cant ask them. Has anyone done stool samples before and please could you advise me if the 3 sample pots mean 3 samples from 3 separate stools, what day i should collect them and where i should be stored? Its Friday today and i need to take the samples in on Monday