How do I match my multi track session settings to my imported file's bit rate?

I'm attempting to merge 2 large m4a audio files created previously via a Zoom recording. The original board meeting recording for both files was recorded at 126 kbps. How do I ensure the multi track session's sample rate and bit depth are as close a match as possible? None of the templates seem to be anywhere close to what's needed, so now I'm unsure the math I did converting those sample rate hz and bit depth bits is correct.  Please help!