This summary is not the rule. The rule text controls.
This rule explains what kinds of money or property can be grabbed through a court order called an attachment, before a case is even finished. Basically, if a regular money judgment could later be used to collect from someone's debt or property, that same debt or property can also be attached earlier in the case, while the lawsuit is still going on.
The rule also explains who counts as the "garnishee." A garnishee is the person or company holding the money or property that belongs to the defendant, like a bank holding funds in someone's account. The rule says the same rules that apply to identifying who holds a debtor's property also apply here. The only difference is a wording change: anywhere the other rule says "judgment debtor," for attachment purposes it actually means "defendant," since the case has not been decided yet.
In short, this rule connects the attachment process to the normal rules for collecting on a judgment. It makes sure that if money or property could eventually be taken to pay a judgment, that same money or property can be locked down early through attachment, and it clarifies that the target of this action is called the "defendant" rather than the "judgment debtor" at this stage.