First pick a piece of wood to saw.
Next with a carpenter square measure how much of the wood you want to cut off and make a mark.
After you make a mark make a" V" at the end of the make and make a straight line around 3 sides. This makes it easier to see if you ae cutting straight.
With a clamp place the wood on the table and use the clamp to keep it in place so when sawing the wood doesn't move.
After using the clamp to place the wood with a saw make a small slit on the mark so that you can cut easier.
Continue cutting the wood until you reach the end but keep making sure that its is straight using the other 2 lines on the side.
If you have a knot in wood it makes it harder to cut.
There you have it you have learnt hoe to cut wood.