I am afraid it is one design and one format at the time. As I have a number of machines that use different formats I usually DL each design three times.
Packs are sorted per format. They usually contain 10 designs or a complete alphabet.
Have fun downloading - and think of a nice way to put them straight into separate files/ categories. It saves a lot of time later when searching for a design.
It depends on the file being downloaded. If the design file has a group of designs in it then all designs within the file are being downloaded but if a design file has only one design then only that design is being downloaded. Each file regardless of how many designs are in the file or zip file are downloaded at one time. You can place all the files you have downloaded into a folder and therefore each download can be directed to the folder where you want them stored but each file is downloaded independently. I hope this makes sense. Have fun with your membership