In this example, the top track is the midi file. The second track is the first verse, and the last two tracks are the second verse.

In the first recording track, I've selected everything in front of where I started recording in that track.

Then I do Generate -> Silence to retain the space of the intro.

To join the two verses, I do Generate -> Silence again from the end of the first verse's track, to where I started recording on the second.

Then I copy the lower track to the upper one.

And delete the lower track. I repeat these last two steps for however many verses I had.

To edit out mistakes, I delete the end of the track, keeping in mind where I started over in the next track (in other words, I delete to a place where the join won't be noticeable).

And then, I set my cursor on the next track, at the point where I just deleted from the previous one.

I select through to the end of the track and cut and paste it into the top one.

Then I delete the lower track, and repeat for however many mistakes I ended up making. I should note, that in this example, I have a separation between connecting verses and editing out mistakes, but in reality, I just move from the beginning of the recording through to the end, so I might do two mistake corrections, then a verse join, then another mistake correction, then a couple more verse joins, and so forth.

Finally, I delete the midi track.