When emulating the Spectrum, the alphanumeric keys (along with Enter and Space) are mapped as-is to the Spectrum keys. The other key mappings are:
emulated as Caps Shift
emulated as Symbol Shift
emulated as Caps-0 (Delete)
emulated as Caps-1 (Edit)
emulated as Caps-2
emulated as Caps-5/6/7/8 (as appropriate)
emulated as emulated as Caps Shift-Symbol Shift (Extended Mode)
Some further punctuation keys are supported, if they exist on your keyboard - ',', '.', '/', ';', ''', '#', '-', '_', '+', ';', ':', ''', '"', '<', '>' and '='. These are mapped to the appropriate symbol-shifted keys on the Spectrum.