There are several ways to do this.
First off, both your mic and the 78rpm records are mono sources but, to playback in a standard CD player, your final results have to be stereo files.
If it was me, I'd probably plug in your mic and, in edit view, record a bunch of voice files. Save each one with a name that makes sense. You can do these recordings in mono.
Then I'd record the various records, saving each of them separately.
Then open the Voice ident for the first track you want--hit "Edit/Insert in Multitrack session". Open the appropriate record track and insert that in multitrack too. Go to multitrack view and you'll have your voice in track 1 and the music in track 2. Right click and hold the record track and drag it to the right so it starts after the voice finishes--you can put in as much or little space as you want.
When you're happy, click Edit/Mixdown. This should give you an option to mix as mono or stereo--select stereo. When the mix is finished, save it with the name you want to use. Repeat for all your tracks then make your CD.
In the midst of this you can tweak levels, add noise reduction, whatever your want.
It's also possible to do all the above in Edit view but the above was easier to explain.
Bob