Using Audacity 3.1.3
When u have a lot of tracks it can be pretty annoying to scroll down especially when u want them to time properly and the tracks are only a few seconds. To do this u just need to hover over the part where the clip name is displayed. You will see a white hand after which you can just click and drag the clip or track to the other track.
If u want to merge them completely later then all you have to do is select all the audio segments and then go to track → mix → Mix and render to new track. It will generate a new track which has the clip segments as one. I recommend this so u do retain the segments in case u want to edit it again