To transpose you should know relative positions. The default base key is C. If the song is in G and you want to raise it to Bb, that would be G-G#-A-Bb, 4 steps. So you should count from the base key: C-C#-D-D#. You can choose D# or Eb to see which gives you better transposed chords. Once you have decided on say Eb, that becomes the new base key and the next time you want to transpose any other song you have to count from Eb. Each transposing routine only affects the song immediately below so you can set every song to your liking. The base key affects the whole page.