I'm going to conduct an experiment and have some questions and hope this is the correct place to ask them

Part 1 of the experiment: There are 2 kinds of groups of participants in the experiment (let's say A and B). The participants have to look at 10 videos in total and for each video, they have to answer yes or no.

Each video has a truth value: either the video is correct or not (true or not true). So the participant is right with their yes/no answer or not.

Part 2 of the experiment: And after they performed part 1 of the experiment, there is some additional information that is provided by me.

Part 3 of the experiment: Then they have to do the same (look at 10 other videos (of the same kind with the same subject)) and answer yes or no for each video.

Q1: How many participants do I need for this experiment to be able to do statistical analysis (how many of A and B or combined)? Is it 30? And 30 in total or 30 of A and 30 of B?

Q2: Is showing 10 videos enough trails per part of the experiment or what is the minimum required number of trails needed? I tried to google this a lot of times but am still unsure.

Q3: And what kind of statistical analysis is best to use to see if there is a difference between the number of times A vs B got the correct truth-value (so correctly say yes when the answer is indeed yes and no when the answer is indeed no), and to see if there is a difference between before and after part 2 of the experiment for both A and B and between them? Maybe a mixed ANOVA within- and between-factors? Or maybe something additional to that of something completely different?

Thanks a lot