You hold a crooked knife in your right hand (if you're right-handed) with your palm up and with your thumb along the bent part of the handle. You cut towards your body as if it was a one-handed draw knife. The native people didn't have a vice to clamp their work in so they held it with one hand and used a crooked knife with the other. 
Here are the awls. The lower one has a triangular blade which is better for making holes in birchbark because it is less likely to split the bark.
The size of the awl you need depends on the thickness of the spruce roots you are using. You want the hole to be just big enough to get the spruce roots through.
Birchbark forms the outside of a birchbark canoe.The bark is used inside out, the white side is on the inside and the pinkish inner side is on the outside of the canoe.
The bark comes from a White Birch tree, this tree is common throughout Canada and the northern United States. White birch trees need light to grow so they are found on burnt over land or where trees have been cut, or along the sides of roads. Birchbark is a wonderful material that can be cut, bent and sewn. It is waterproof and resists decay.
Finding a suitable birch tree for making a canoe is not easy. To start with, the tree has to be very straight and without branches or large knots for the length of your canoe. Then the bark has to be thick enough and flexible. It should be at least 1/8" thick and 1/4" is better. To test the bark, canoe builders remove a sample piece before cutting a tree down. The bark must not split apart into layers and it must not split along the eyes when it is bent either way. The eyes should be short and widely spaced. The circumference of the tree is important since this will dictate whether extra side panels will be needed but the quality of the bark is more important than the size of the tree.
To use birchbark it has to be removed carefully from the tree. You can either cut the tree down or remove the bark while the tree is standing. I am told that removing the bark does not harm a birch tree but it never grows back so I would think it would leave the tree vulnerable to disease.