To send out multiple appraisals at once, use the Batch Operations > Launch Appraisals option on the Appraisals page.
You can select the entire organization at once or you may want to select only a specific department, job title, location, etc. If the latter is true, click on any of the column headers to sort your employees using these categories.
Click on the Columns button to view all the possible sorting options and select reviewees based on your criteria.
Once you have selected which employees will be reviewed, you will then be asked to choose self-review deadline, manager deadline, and questionnaire (same as with a single launch).
Be sure to press Next and then Launch to finish the process.