Adding to existing recording

I’m a guitar player that has used this program in the past to record and edit files. For the life of me though I can’t figure out how to record a part…then stop…then record another part and add the recordings together as one? I’m trying to mix an acoustic song for my wedding in 2 weeks to be played as she walks down the isle! I have the entire song but I want each part to be perfect so I’d like to record each part separately then mix them together as one. I know I’m missing a simple step here. Just running out of time before my wedding…please help!

What about “Shift+R” (“Transport | Append Record”)?