The powerpoint could be used in a variety of ways, but this is how I usually run the activity.
Put students in groups and give each group something to write on, such as a mini whiteboard or a large piece of paper with an appropriately-sized marker. Show the example slide and explain that they should write out the whole sentence, including what should go in the blank (twice, three times, half, etc.) and one of either "much" or "many". Then, for each slide, give groups 1-2 minutes of time to write out the whole sentence. I usually like to walk around as students are working so that I have an idea of which groups have the right answer. Once the time is up, all groups hold up their whiteboards or papers for the teacher(s) to check, and are awarded one point if their answer is correct. (The score is tracked on the chalkboard.) There is also a bonus question at the end, which I usually make worth more points.