Hi Terry,
Welcome to this Microsoft Project newsgroup
This is rather like the question "How long is a piece of string?"

Assuming all your resources are capabable of undertaking any or all of the
tasks, then enter your Resource as a single name, eg Workers. In the
Resource Sheet view enter the Max Units value as the total number of
workers. For each task, enter the resource as one worker, ie 100%. Now
resource level. This will tell you how long the project will take with the
number of resources you entered in Max Units. Then you could try reducing
the Max Units and re-levelling (Clear Levelling first) and see how long that
takes. This will give you a crude way of seeing what is possible.
Another way is to enter your resources by name and assign to appropriate
tasks and level. See what the end date is. If it's taking too long, Clear
Levelling, and look for the longest task on the critical path. Add a second
resource to this task and level. Continue as necessary until you get an
acceptable date.
There are infinite number of possibilities, and I'm sure others have
different ideas, but this will get you started.
FAQs, companion products and other useful Project information can be seen at
this web address: <
http://www.mvps.org/project/>
Hope this helps - please let us know how you get on

)
Mike Glen
MS Project MVP