Knitting consists of loops called stitches pulled through each other. Let's start with some basic patterns.
The lower red course is knit into the white row below it and is itself knit on the next row; this produces stockinette stitch. A baby blanket is the perfect place to practice more complex pattern stitches. These different materials need to knit the fabric are as follows:
For an easy or beginner level there are usually easy patterns, like different types of scarf or shawls or even some sweaters with easy knitting patterns. Plants used for fibers include cotton, flax (for linen), bamboo, ramie, hemp, jute, nettle, raffia, yucca, coconut husk, banana trees, soy and corn. The other advantage is that these patterns are in effect free.
Even if you're a pretty proficient knitter, this isn't the time to learn a new technique or work with a skinny fingering-weight yarn that will take forever to knit up. Be sure to try using other available resources, such as local craft and hobby stores.