Kinder Quilter answered:
I start by cutting the shirts up the side. Use a 12" square to cut the parts you want to use. Either front, back, or both. Once you have your squares, cut your sashing material. This will be Iin between each block. I do the right side only first. Because when you lay them out each right side will be the next blocks' left side. ( make sense?). The top sashing is sewn in one strip to go across the entire row. Just make sure you have enough t-shirts. 6x4 is 20 shirts- rectangle, square quilts can be 5x5, or 4x4. It just depends on which size and shape you want. I hope this helps. Let me know if you need my help. I can email you or talk on the phone. Thanks!