I am trying to learn how to make a yarn rug. its a certain kind but I can't find instructions anywhere.?

I m not sure if this is what you mean but I make a pram blanket using a similar style.the nails go round the outside of the frame approx 5 cm apart. there are no nails in the middle of the shape.Starting at a corner tie the yarn round the nail,wind the yarn up and down each row till last one done then go across the way in the same manner until you get to the end.You then have a grid like effect.do this until you think it is thick enough and then tie end of yarn to last corner.At every cross over of lines tie the join together with a piece ofyour yarn.THen you cut about half of the number of strands in each line(if you go round 4 times cut 2 strands)this gives the shaggy look to your piece.you need to use nails about 4 inchs long so that you can get plenty of yarn round them.To get it done quicker use 2 strands at once.If you use 2 colous one after the other you could cut only the 2nd colour and that gives a nice effect.try it on a smaller scale to practice before trying to do your rug .You may need to get some one to make you a frame for the nails to go into but to practice on you could try a wooden picture frame.good luck and i hope this was helpful.