Roland D-5

The Roland D-5 patch editor works in the synthesizer's Multi Timbral Mode. To use the editor, make sure your synth is set to Multi Timbral mode. Also, use the top-right settings menu (the gear icon) to choose which of the 8 parts you want to fetch/edit. The MIDI Channel setting in that menu controls which channel the notes of the In App keyboard are sent to, so you should set that to match the part you are editing, for easy testing.

The editor edits the synth's "tones", which are the main component of a sound for the D-5. But additionally there are some settings that are part of the "timbre" and these are found in the bottom row of the editor, and they are independent of a "tone". Tap the "Timbre Sync" button to update the values of these controls to match what is on the currently selected part on your synth. You can change these settings (e.g. the reverb settings, and transposition) using the bottom controls, but these settings are not saved; only the Tone is saved (all of the control rows other than the bottom row).