For certain patterns you need to knit with more than 1 strand of yarn at the same time.

If you want to, you can wrap all of your strands together before you start to create 1 giant ball of multiple strands, or you can work with the strands coming from different balls.

Knitting with 2 or 3 strands together is exactly the same as knitting with 1, just thicker.

Just make sure to knit all of the strands at the same time, as if they were one thicker yarn.

Casting on is the same as normal as is knitting and purling.

Using multiple strands of yarn at once creates a thicker, heavier fabric than knitting with 1 single strand.