Hi there,
New to the forum, when recording with Audacity I noticed that everytime you click record it creates a new later which is great! However if I want to record on the previous layer is there a way to do that instead of having to copy and paste my newly recorded audio into the previous one? 
You can hold SHIFT and press Record (or use the SHIFT + R shortcut) to Append Record to the end of tracks which are selected.
If you have a recording on a separate track you do not need to cut/paste it into the track above as it will automatically be mixed into the other tracks when played or exported.
Gale
Thank you so much!!