You may want to take a recording and split it into two separate recordings, or combine two recordings into one. You can do this easily in reaper.

Turn off the magnet

If you’d like to split or glue a two takes that are not perfectly lined up on the grid, you’ll need to disable “grid snapping”.

Just click the magnet in the top left tool bar or tap alt+S on the keyboard.

Split a recording

Select the recording by left clicking on the waveform itself. The recording will highlight when it is selected and the green time marker will appear where you click.

Put the time marker where you want to split the track by clicking on the waveform in the desired location.

Press “s” on the keyboard. Or, right click on the waveform and select “Split Items at cursor”.

Glue two recordings

Make sure both takes are highlighted by holding “SHIFT” and clicking both takes.

Then, right click and select “Glue Items”.