Can't use screenshots, but I'll try to explain with text only.
The data elements are completely independent from rules. So you could use the same data element in multiple rules and assign it to different eVars or props in these rules.
To use the data element, you need to have a rule and then in the action section add an Action with the Analytics Extension and select the Set Variables. There you have the eVars, props and events where you can select your prop55 from the dropdown and next to the value field is the database icon, where you can search for your searchTerm data element.
Also don't forget to add a Send Beacon action (also from the Analytics Extension) if you want to have this prop tracked with this rule.