I cant tell you how much yarn you will need as I used some I had hanging around the place but I imagine if you allow about 150grams it should be plenty.
I used 8ply and a 4.5mm hook. You will need to translate this to your sizes.
The pattern is written in US terms.
CH = Chain, DC = Double Crochet, SS = Slip stitch, SP= Space, STS = Stitches.
Make 60 chain and join with a slip stitch to make a big loop, taking care not to twist.
Row 1: 4 ch (to stand as 1 DC and 1 CH), 1 DC into base of CH, * miss 1 CH, 1 DC, 1CH, 1DC into next CH, * continue from * to * to the end of the row. Join with a SS into 3rd of 4 CH at the beginning of the row. 30 V STS
Row 2: SS into the first 1 CH SP, 4 CH, 1 DC into same SP. Work 1 V ST onto each of the next 6 1 CH spaces,* Work 1 DC, 1 CH, 1 DC, 1 Ch, 1 DC, 1CH, 1 DC into the next V ST*, work 1 V ST into next 14 V STS, Repeat *to * then work 1 V ST into each of the next 7 1 CH spaces. Join with a SS into the 3rd of the 4 ch at beginning.
This last row forms the pattern and is continued to the length required. There will be 4 extra V STS in each round thus forming the points of the Poncho.
You can put a shell pattern around the edge by working 1 SC into the 1st 1 CH SP, * 1 DC, 1 CH 5 times into next SP, 1 DC into same SP, 1 SC into next 1 CH SP* Repeat * to * around the edge, being creative when you get to the increases at the two points. Fasten off and finish off any ends. Because I had 2 different Batch lots of yarn, I put 1 round of a contrast yarn so the colour difference would not be so obvious. You could also put a fringe if you wanted to and leave the shell pattern off. The loops are there for you to hook the fringe into.
The neck can be left how it is or you could work a round of SC on the neck with a row of eyelets to thread a cord through then another row of SC.
Make the cord by crocheting the thread double and making some little bobbles on the ends so the cord does not pull out.
Hope you enjoy working this pattern.