The alignment editor allows you to -guess what- align two songs. This is done by shifting back and forth the new song whilst keeping the old song at a fixed position. The alignment editor can be opened by long-clicking on the transition. If the transition was already open, then click on the button. Ordinarily though the alignment editor is opened by default. The alignment editor has 5 handles.
The most important one is the beat aligner. This allows you to shift the beatgraph up and down, allowing an accurate alignment of the two beats. If the icon has the text 'fast' then the shift is quantized on 1/16th notes. Thus: first align the beats using the fine grained control, then align the bars using the coarse grain control. The beat aligner can be toggled by briefly tapping it.
The margins (found at the left and right boundary of the transition) specify at what position the transition segment begins and at what position the transition segment ends. Both together specify the length of the transition.
The song dragger allows you to delineate the new song by removing any unnecessary introduction. It also makes it possible to appropriately align the two songs by having their phrases (sections of 8 measures) aligned correctly.
The transition dragger allows you to move the new song, including the margins. Generally, this handle can be used to delineate the old song. Parts of the old song that are no longer necessary can be removed with this.
can be used to finetune the start and stop positions of the transition. The first one moves both the start and stop position up and down (preserving the transition duration). The second one, moves only the stop position up or down. Toggling between the two handles can be done by simply tapping the current one.