Auto Functions/Template

I am trying to set up a Template to calculate employee PTO (personal Time off). The business has been opened for 2 years, so I have to back track and add the date (ex. 3/7/05-3/20/05). This is our pay period, 14 days.
Does anyone know how to auto calculate dates? This part is probably, so far, the most tiresome part of setting up. Plus the business has 21 employees that this needs to be done for, all with different hiring dates.
Also if anyone can offer any suggestions on how to create a template that would be great!
Thank You
Melissa

Not a planner, im attempting to set up a Template to input regular hours and have the template automatically calculate PTO.
The way we do it now, we have to calculate hours worked from the first day of employment to present then calculate the PTO.
With the spreadsheet, I would like to just have to but in the hours worked every 2 weeks and have the template calculate what is owed to them and subtract hours used.