Inspect the hay condition first to set the width of your rake. If the hay is dry, you can rake three windrows at the same time. However, if the hay is wet and green you might need to reduce them.
If the hay is heavy you will need to set the rake to three windrows with an eleven wheel rake. With the passage of time you learn to observe condition of the hay more effectively and this will help you to set the rake accordingly.
To rake you will need to drive to one end of the field and choose the rows you want to start raking from. Picking row is not a technique that can be mastered. Just drop the rake and the rows are automatically picked.
It is better that you rake the area which is exposed to the sun. The hay in the field under some trees or shadows can take some time to dry. So you might not need to rake them at the same time you rake the hay in the field that is open under the sun.
While driving the tractor watch the front of the rake to make sure you are picking all rows. Drive straight down in the rows and make sure that the hay is flown over at the back of the rake. If the rake is plugging up the hay, it might turn upside down and possibly the wet part of it will remain underneath.
At the end of row, you will need to turn around the tractor. Just drive out of the field little bit so that all hay is raked and then lift the rake and turn around. Do not leave rake down on the field while turning around, it can damage the rake.