You can activate the workflow from one of the options, as seen in the image below.

After enabling the Active toggle, Torii will ask if to run the workflow on:
A) Users, applications, or contracts that will match the criteria after the workflow is activated.
B) Users, applications, or contracts that match the trigger criteria now.

Select option A if you are looking only for future optimizations.

For example, you might decide to send notifications about apps connected to Slack that have a high-security risk to your security lead.
To prevent dozens of notifications for apps already connected to Slack and approved, select to enroll only applications that will meet the criteria after the workflow is activated.

Select option B if you are looking for both retroactive and future optimizations.

For example, if your company decides to work with a Zoom vendor, all full-time employees must be assigned to a basic Zoom license.
You can create a workflow that automatically assigns licenses to users whose status in BambooHR is active and run it on all existing employees who are active now.
Note that you can see the list of users (or other entities) that currently meet the criteria at the bottom of the popup. This list is identical to the Preview list.

After selecting, click Activate.
If you select to run the workflow on current entities, it will start running immediately.
You will get a message that "The workflow was activated" and a popup that will enable you to navigate to the Logs page.

On the Logs page, you will see the workflow progress.
Note that for a workflow that ran in bulk retroactively, the process might take a while. Use the Refresh option to view the runs' progress.