First thing is to collect all old t shirt that you plan to throw away. And start cutting each t shirt in equivalent pieces just as shown on the picture and tangle it so it can be more easy for knitting. The point in this DIY T Shirt Rug project is that you are going to do the knitting with reusing your old materials.
When you are done with the each t shirt at the end make small gap as shown on the picture bellow. And same gap on the begging on the next t shirt.
Than put each part above other and try to connect them as shown bellow, than continue with cutting the t shirt in nearly same width and tangle it.
When you are done with all t shirt start knitting. There are so many knitting tutorials on the net, so for saving your time just go on this link where you can see exactly how to do the knitting, its a youtube video.