Go to Employee Management :

On tab n° 5, sub-tab OASI/Unemployment/AF

If there is only one OASI fund, it will be proposed automatically. If there is more than one, simply scroll down the contract to select the relevant fund. (If you are unsure of the settings, see here)

You should NEVER uncheck OASI and unemployment (unless you are managing expatriates or other). Even if someone is too young/old, they should be left ticked since the program will decide on the basis of the date of birth what to calculate (it starts on January 1st of the year in which the person turns 18, and the month following the age of retirement, it stops the unemployment and takes into account the deductible of 1,400 for the OASI).