Yarn
Which yarn can I use for the patterns?
In all the patterns, the recommended yarn is specified. That means the yarn in which the pattern was originally knit. However, you can always choose to knit with a different yarn than the original yarn. If you do so, it's especially important to make a gauge swatch to ensure that you maintain the correct gauge. Read more about gauge swatches and gauge here. As long as you can maintain the correct gauge, you can work with whatever yarn you like.
There are plenty of options for finding a great yarn alternative to knit a pattern with. You can either choose to substitute one yarn quality with a similar yarn quality, for example, by substituting a mohair thread with another mohair. You can also choose to use a completely different type of yarn, for example, by substituting 2 strands of thin yarn with 1 strand of a thicker quality.