If the chords are not lining up when you display the song in Performance/Stage mode, it will be down to the lines not being recognised as chord or lyrics lines.
The editor window uses a monospaced font (all characters are the same width) to help you line everything up. You will be able to see quickly if chord lines are not being detected if they are not displaying in the chord colour set in the display themes. By default (in the dark theme), the lyric lines should be showing in white and the chord lines should be showing in yellow.
Also, just as a check, you are putting the chord line directly above the lyric line that it is supposed to match up to? I know some people put chords under the lyrics, but OpenSongApp doesn't use that method. There also shouldn't be a space between the chords and the lyrics.
Here is how a standard song should look in the editor window and when viewed in performance mode

You can also use multiple verses linked to the same chord sequence as shown in the images below. Note the use of the underscore _ to split words to help with alignment. These underscores get converted to a hyphen in the song display

Hopefully something here helps?
Gareth