Once you have created your schedule, you are now ready to assign your volunteers to the various positions for that schedule.  To manually fill in your positions, select a day from the calendar on the left and then select a job at a shift that you want to fill in.

The right side of the schedule window is to help you manually assign volunteers.  By default this section will be set to "Fill positions" mode.  This means when you select a position from your schedule, VSP will filter your volunteers to show you who is qualified to serve in that job at that shift.  (Note: The filters can be turned on or off by clicking on the text "Show only volunteers who...".  The filters will open as a drop-down menu, and to turn one on or off, select it and it will then be "unchecked" so more of your volunteers names will be shown.)

You can then drag and drop the volunteer's name onto the position, or double-click to assign them.  

If someone is already scheduled and you wish to replace them, follow the same procedure - dragging and dropping or double-clicking will replace the existing volunteer's name with the new one.