Here are some steps you can use to adjust and clean up your assembly:
Crossfades, which are used to merge clips and help one clip blend more smoothly into another, are introduced here because they are a sound editing best practice. You will notice, however, that Audacity automatically merges sound clips when you click on the split (black line) between them. If you choose to merge the clips by clicking on the split, make sure to listen closely to verify that there is not a pop or click where the split once was. If there is, undo the auto merge (Command Z on a Mac and Control Z on a PC) and use a crossfade.