Starting the program

After starting the program the user is asked:

Use last used model setup?[y]
(Press "o" for other options)

Pressing return or any character other than 'o' or '0' will run the last used model with the user first given the options to change ano and gno (the relative abundance and distribution of the molecule throughout the cloud). Pressing 'o' or '0' presents another menu:

Would you like to:
1. View some old runs.
2. Delete some unneeded runs.
3. Modify an older model.
4. Run several models automatically.
[3]

Pressing enter or any character other than 1,2 or 4 will select option 3. Dealing with each option in turn: