The size of sample group is estimated to be 120 people. Sampling is done by using the Block Design Randomization method (30 blocks of 4) and using the table of random numbers. . In general, the samples are devided in a virtual training group and a control group. In total, 60 people are in the intervention
group and 60 people are in the control group. Thus, the samples were randomly divided into the intervention group (training through WhatsApp + routine care)and the control group (only routine care). In this way, all possible modes of placement including A: Training via WhatsApp and B: Routine care were considered in blocks of 4 with an allocation ratio of 1:1, and the number of required blocks was determined based on the number of samples.
After that, according to the required number of blocks and based on the table of random numbers, the blocks corresponding to each table were listed in order. Finally, as the samples entered the study, each person got a certain letter according to the obtained order .In order to hide the random allocation, the sealed non-transparent envelopes method with random sequence was used. In this method, first, a random sequence is created using a random number table, and based on the sample size of the research(120), 120 matte envelopes (in order to make the content of the envelope unclear) were prepared. Each of the created random sequences was recorded on a card by a person who was unaware of the goals and topic of the study and the cards were placed in the envelopes, and finally the envelopes were sealed and placed in a box in order. At the time of sampling, the researcher, according to the order in which the qualified participants entered, opened one of the envelopes and the group of that participant was revealed.