During the first sitting of a root canal procedure, the following steps are typically followed:

1. The affected tooth is numbed using local anesthesia. This helps to reduce pain and discomfort during the procedure.
2. The dentist will then create an opening in the top of the tooth to access the root canal.
3. Using special dental instruments, the dentist will remove the infected tissue and bacteria from inside the root canal.
4. The root canal is then cleaned and disinfected to ensure that all bacteria and infected tissue have been removed.
5. Once the root canal is clean and disinfected, the dentist will fill the root canal with a special dental material called gutta-percha. This seals the root canal and helps to protect the tooth from further infection.
6. The opening in the top of the tooth is then sealed with a temporary filling to protect the tooth until the final restoration (such as a crown or filling) can be placed.
7. The root canal procedure may be completed in a single sitting, or it may require multiple visits depending on the complexity of the case.