looking for a shortcut key that will work in a macro

Hey ya'll!

I have created a table for tracking rental equipment and have run into a silly hiccup. In the worksheet, if you enter data in the fields with salmon colour (agent_id use drop down menu), then hit loan it will paste that entry under rental_log. If you immediately hit return (under action) it will paste the entry under the previous one but will now include return date and loan duration date as well as clear the input fields. Here is where I am running into a slight problem. If I fill in the fields with different data, and hit loan, instead of recording that entry in the next open row under the return_log heading, it copies it right over the first entry and the same when you click return (over the second). I would like for the entry, either from a loan or return, to be recorded in the next open cell under the return_log. So far, I have tried a number of shortcut keys while recording the macros but they all end giving me the same result.

Any suggestions and/or help with this would be great!