Thanks for taking the time to post here in the Community, Ellice20.
Deleting a pay run can't be undone. You'll want to recreate it to proceed with adding employees to the pay run. You can check out this article for your guide about creating a new pay run: Create a New Pay Run on QuickBooks Online Advanced Payroll
I'm also including some articles related to pay-run in QuickBooks Online for your guide:
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