With this Swantide Workflow, you can auto create an Opportunity when a Checkbox Field (Boolean Field) equals true on Record Create or Record Update for an object (Custom or Standard) that is related to an account either via a Lookup Field or Master-Detail Field Association.
Say that you have a Custom Object called BIN. BIN is related to an Account either by a Master-Detail Relationship or via a Lookup. Within that Custom Object, you have a boolean field called "Exclusive Bin" and when that checkbox equals true, you want to have an Opportunity automatically created for the Account.
Given that use case, using this Swantide Workflow, you would want to set your Variable Inputs as such:
Select the Checkbox Field in Scope - in this case "Exclusive Bin"
Select the Master-Detail or Lookup field that links the Custom Object to Account.
Select the Account Type in scope that the Opportunity should be created for. In this case I selected the Account Type as "Prospect"
Select the Stage in which you want to create the Opportunity in
Select the Lead Source of the Opportunity
Lastly, enter in the number of days out that you want the Opportunity Close Date to be in, once the Opportunity is created.
Once this is in your Salesforce, anytime a record in this case a BIN Record is created or updated and the record is Linked to the Account and the Checkbox field equals "True" then an Opportunity will be created given the conditions you outlined on the Account Record.