Each month you will receive 2 pieces of fabric 12 x 12. The people sending the fabrics will give specific requests, if they have any, of what they would like back in return. For example, some might want a 9" block, some may want you to not use any whites or ecru, some may want you to use only white....some may send 2 different fabrics to be used, some may send you the pattern to be used. If no requirements are sent along...then you just gather fabrics from your stash, make a block 12 1/2x12 1/2 unfinished and return the block to the sender.
When it's your turn to send out fabric, you send a piece of fabric 12x12 to everyone on the list, except yourself of course. Then sit back, make only one block that month for the other person assigned that month and enjoy all the blocks that are returned to you from the other members on the list.