XLF file from Articulate 360

Received XLF file for first time from new client. Had no idea what the format was. Tried to open it in Excel, Wordpad, etc. before noting that Trados was mentioned in many forums as a relevant programme.

In contains content in Spanish to translate to English. 

I eventually worked out I could open it using the "Traducir documento individual" option in my Trados "Archivo/Abrir" menu. But the pop-up window before opening the document asked me for the language pair, detecting (erroneously) US English as the defect source language. So that adventure ended there.

Apparently the software used for the client's presentation is Articulate 360. 

Anyone have any idea how I should proceed to avoid having to download and pay for Articulate 360?

Much appreciated any help you can offer.