The B main and F key chords are generally performed as barre chords, with the first finger depressing 5–6 strings. Just as if notes were being letters and chords have been text, this system of numbering is called spelling. On the web, you can find a lot of chord diagrams, https://chordtela.cc/chord-taylor-swift-come-back-be-here-taylors-version-mp3.html