Estimation is typically done based on experience or a set of quick calculations. For example, this project would take one designer and one developer two months, at $150/h, totaling $96,000 in billable labor. If at all possible, keep estimates and subsequent proposals high level and accurate, rather than calculate every minor expense upfront.
In 10,000ft, you can create a new project then assign people (or Placeholders for roles and disciplines) for the amount of time you think it will take to accomplish it. The resulting “Future Scheduled” amount is the estimate for this project.
When the project becomes a reality, this estimate turns into the budget. When future assignments are made to the project, the resulting future scheduled amount should be up to the budget.
When you schedule too many people or too much time to a project, it will be immediately apparent that this project will go over budget if you continue with this plan.
If you don’t schedule enough people to a project, consider whether you will have the right resources available when you need them.