@Alexis Rua I'm getting the impression you've got a number of things going on here that you need to work through, and there's not enough information in your post to fully troubleshoot, but I'll take a stab at it: The first issue is how 'Record is parent' option works. I'm not clear on exactly what you're expecting to happen, but the point of this option is to allow your custom record to link your record to the parent and display it as a sublist in the parent record. You will definitely need to have all your 'Record is parent' records created before you can create your custom record, so yes, you'll need to have the case already created, and then use the "new custom record" button in the subtab of the case to create your new custom record with the case automatically populated. If you don't create your custom record that way, then the case value on your custom record is not automatically populated and then there's nothing for your workflow to source.