A simplified explanation.
When first working with the clay it has 3 stages.
The clay is wet and wedged to remove air pockets and inconsistencies in texture. It is the first stage of working with the clay creating shapes, vessels, pots, mugs, bowls, sculpture, etc.
The clay is still moist, but has firmed up enough to work with other applications including, but not limited to, carving and sgraffito; adding underglaze decal transfers; adding elements such as handles and shapes.
After the work has had time to fully dry (and this takes time as work is covered with plastic or put into a drying box for a few weeks so that it dries evenly which avoids cracks and warping), it is then put into the kiln for the first firing called the bisque fire. It takes about 24-48 hours for this firing including cooling time which is critical to avoid thermal shock which is when the kiln is still hot and collides with the cooler atmospheric temperature causing pieces to crack or shatter.
After the clay has fully dried and gone through its first firing, it is ready to be glazed.
When glaze choices are then applied to bisqueware.
After all glaze colors have been applied either dipped, brushed, poured or sprayed, pieces are then ready to go back into the kiln for the second firing called the glaze fire. It takes about 24-48 hours to glaze fire including cooling times, and happens at a higher temp than bisque firing.
The work is now complete and ready to pick up and be displayed or used for its intended purpose.
Works take 3-4 weeks start to finish.