How does one change the name of a unit in EBfD?

[mugwumpjuice]

I know how to switch units to be built by other houses but how do I change the name of those units to go with the new house? Example: if I've made Harkonnen Buzzsaws a Sardaukar unit how do I change the name to reflect that?  I did a search of the forum and found a thread where someone asked the same question and they were answered.  That post said to edit unit names in the strings file but the post doesn't say how to do that, where it is, etc. 

Looking in my Emperor folder I found some RFD and RFH files called "STRINGS0001" and "STRINGS0002" (I couldn't find any others) but when I attempt to open them my comp asks me which program I want to use to open them and the only choice I have is to go to the Microsoft store to get a program for that. If this is what I have to do what program would I use? Once the change is made is there something else that has to be done?

 

Thanks!