Q:

Sorting tasks to assign

I've got a problem that I don't know where to start. I'd realy appreciate some help.
The problem:
I have several T task that must be done in D days by just 1 employee (let's forget using several resources right now). Each task can be done in some times (not all tasks can be done all time). e.g.: If my employee starts working at 8 o'clock and one task is "call a client". Maybe the client office opens at 9 o'clock.
Also each task has a duration (really estimated). It is supposed that the D days are enough to do all task.
I've to sort the tasks to the employee. e.g.: at monday 8:00 do task 7, then at 9:30 starts with task 2. In the example task 7 duration would be 1 and a half hour.
Thanks for the help!
Diego
PD: If someone has a way to make this and it is not an algorithm never minds, please answer and I'll manage to think the algorithm. I just don't know how to face the problem.
Edit
Would Project be usefull?
Edit 2
Tasks / Jobs dependency is NOT required

A:

If this is a "little part of an app" you might want to renegotiate with the client: Job shop scheduling is NP-complete (vulgo: gets real difficult real quickly with increasing complexity).
Some points to ponder:

you need to assign some sort of "capacity" to the days, marking time intervals when some sort of task is possible (work start and work end of your employee, opening hours of other offices, etc.)
you need to tell the different tasks (or jobs, as they are called) what sort of capacities they require, and for how long: tools needed, people to be reached, etc.
you might need some sort of directional relationship between, say, job 17 ("call office XYZ and ask for cost estimate") and job 18 ("forward cost estimate to boss"): job 17 must be done before job 18 can be started.

When you google for "job shop scheduling" you'll come across more scientific papers than you'll ever want to read for a "little part of an app"...
(Disclosure: I work for a company that offers different tools to do just this sort of thing.)

