Just type what you are looking for, or click “More options” and choose a yarn, category or technique (you can use all or some, no field is mandatory).
You can also search for a specific pattern, by either writing the pattern name, the pattern model number (i.e. de-120) or the pattern DROPS number. Here's a few examples:
Searching for type and number (i.e. DROPS 120) will show a complete catalogue.
After you make your search you will be able to filter your results by knitting tension, hook size, colours, etc.