Units

I will use the metric system (grams, litres etc.). But some older and american recipes use different measures.

Flour can by measured by it's weight and is usually given as ounces (oz). In American recipes it is measured by volume (how much room it takes) and it is given as cups.

There are online convertors like this.

This is from http://www.epicurious.com/tools/conversions/convertingtometric