First you knit the sleeves, and then the rest around. In the end, you bind off, and you are done!
Increases are made several places on a round, so it is a good thing to have stitch markers ready.
You can choose to knit it in one colour, or with stripes as shown on the sleeve in the Picture.

The English website: http://www.geilsk.com/store/products/cardigans/second-tho...

The German website:
http://www.geilsk.de/shop/produkte/strickjacken/bagtanker/

The Danish website:
http://www.geilsk.dk/butik/produkter/tr%C3%B8jestrik/bagt...