Just like with a video dissolve, you need enough source material before your in point to overlap the previous clip. Move your in point slightly later (half the dissolve duration), and it should work. You may have to move your out point in as well.
Select the clip(s) to copy, then select copy from the drop down menu (or right-click menu), or use ctrl-C. Then park your timeline cursor at the beginning of where you want to paste. Make sure the track you want to paste to is selected (click on the track header box where the eyeball and track lock boxes are, so it turns light gray), and paste (ctrl-V).