How it all starts
First to start a fused glass design you must choose your glass. There are many different types of glass, but whichever is chosen...they must all be compatible. I use Bullseye glass which is 90 COE. The COE stands for Coefficient Expansion. This has to do with how the glass contracts as it cools. If two glasses are combined that don't contract at the same rate, then the glass will shatter after or during the cooling. Sometimes it can be a month later.
Now, back to the types of glass. There is flat glass and ground glass called "frit" and stringers/noodles which look like spaghetti or fettucini noodles. There is also "liquid glass" which is very finely ground glass in a liquid suspension. They come in all sorts of colors, transparent, opaque, translucent. Also there is iridescent and dichroic.
To make a plate or bowl you can start with a round flat piece of glass for the base. Then you can add additional layers on top with more flat glass, frit, stingers etc. Then this is fired in a kiln at around 1,400 F.
After this is fused it becomes one flat piece of glass. Then this is placed on top of a slumping mold and fired a second time at about 1,300 F, where gravity pulls the softened glass into the mold and thn cools slowly.