trebel crochet stich is little bit tricky but easy to learn.it is little bit longer than double crochet.you can make many things with this trebel crochet stich.
lets get started
1)tie a knot
2)make chain 15
3)yarn over twice.
4)yarn over hook and insert it into third chain from hook.
5)yarn over again and pull through first two loops.
6)yarn over again and pull through from next two loops
7)yarn over and pull through from last two loops on hook.
8)repeat that stiches in all over the chains.
9)chain one and flip the work.
10)repeat again complete the next row.