Need help with Super Scratch Programming Adventure

Hello, I recently signed up to scratch and bought the Nostarch book for my sons, ages 5 and 8. We've been able to do a few small projects with scratch, but nothing exciting and our drawing is horrible for making our own costumes, designs etc... We are not IT experts by any stretch of the word, just a pretty average home educating family looking for new learning experiences. We have downloaded the resources for the book several times but don't know how to get them into the scratch programme. I contacted No starch, who said they do not troubles shoot or apparently offer any customer assistance but to ask here. If any one could help we would certainly appreciate it. As it is we can't get past the basic cat walking around in scratch as the book I wasted £10 + on is of less use than ice maker at the north pole. Thank you for your time in reading this.