This is an interesting subject. Glassblowing is a demanding skill. You can read more about it right here. There are several methods of glassblowing, but we will explain two major methods.
The first method is called “free blowing”. This is an old method, but it is used even today. The method used in the ancient period is not well studied. We lack information about glassblowing techniques used in that period. It is most probable that blowpipes used in the ancient times were not too long, which was making glassblowing easier. Those clay pipes could be used more than once and were quite easy to use. This method is used today and skilled glassblowers can make great glass shapes by pipe rotating. Another important thing here is to control the piece temperature during the glassblowing process.
The second well known method is called “mold-blowing”. It appeared some time after the free-blowing method. This method is based on the following steps: first, molten glass has to be put onto the blowpipe end and then it is inflated into a mold made of metal or wood. This mold is carved, so the glass texture actually depends on the way the mold is carved inside. There are two models of molds: a multi-piece mold and a single-piece mold. If using a single-piece mold, you can easily remove the glass after you have finished your work. This is done by pulling the piece out of the mold. A multi-piece mold is used for making more complex shapes and textures.
If you want to learn how to blow glass pipes, you have to be very careful not to burn yourself. You have to melt the glass and then take a tube, which you will blow in order to make pipes. When the glass is formed, shape it. Then pull it out and leave it to cool.