If the salary is $40,000/year you take that amount, divide it by 52 weeks.  Divide that by 40 hours (if that's a normal work week) and then multiply that times 8 (if that's a normal work day) and you will have your daily rate.  

You will choose the "salary" item, put in the amount for that pay period and make sure you choose the correct number of hours....let's say 8 days at 8 hours per day, would be 65 hours.