Access database to manage employee locations

Need a Access database in .accdb. I have 20 work sites, up to 80 different positions at each work site that need to be manned 100% of the time. I would need to maintain a list of my employees with which positions the are authorized to perform, their current locations, how long since the last time they have been scheduled and if they have any Leave of Absence. I need a form where I select the Site, Then position to be filled, then what skill it requires, the dates the employee will fill the position and then which employee is available(an employee not scheduled in another position and is not on a LOA), Employee's should be sorted based on who has not be assigned in the longest time. Have a Save button to check the last person to be assigned to the position and any people in the future in a effort to verify multiple people are not assigned to the same position or something similar to prevent double booking of the position. I need to be able and view each site and see by day and week who will be filling each position at each site. The positions should be rows and the date column. The person in each position for that period will be the value.