The Bank Editor works slightly different for the DX200 than other Patch Base editors. When you make changes to the Pattern Bank in the Bank Editor, or when you save a Pattern to the synth from the Pattern Editor, these changes are not automatically sent to the DX200. They are only saved on your iPad in the current bank file in the Bank Editor. To transmit any bank changes you make to the DX200, you must tap the "Send" button in the top right of the Bank Editor, to transmit the entire bank to the DX200.
Why does it work this way? Because the DX200 can't properly accept updates to individual patterns via MIDI, so the entire bank must be sent at once. And because this operation takes a relatively long time, this editor was designed to only execute a bank update manually.
It is highly recommended that you use a wired MIDI connection (i.e. not WiFi or Bluetooth MIDI) when transmitting banks to the DX200. Wireless MIDI will often lose some information in the transmit, and your banks won't sound right as a result. This is an inherent problem with MIDI over WiFi or Bluetooth.
When you send a bank to the DX200, part-way through the send the DX200 will probably start flashing "Err2". This seems to be normal; even when sending a bank from a computer via MIDI, the DX200 does this. Just press "Exit" on the DX200 to make this go away.
The Free EG editor lets you touch-edit the 4 Free EG tracks in a DX200 pattern. Here are the different 1-finger tools you can use to edit envelopes:
You can also zoom and pan in the Free EG editor:
You can import individual DX7 patches and patch banks into the DX200 editor, so that you can try out different synth sounds separate from pattern data. Just tap the "Synth" button in the top-left of the editor, and you'll see a separate file area for DX7 patches and banks. With this pop-up window, you can tap the "Save" icon at the bottom to save the DX7 sound from the current pattern to this area. You can also choose a sound from this area to load that sound into the DX200 without changing any of the rest of the pattern (something that isn't possible on the DX200 itself!). This pop-up window works the same way that the patch browser on the right-side of the screen works; except the pop-up is just for DX7 patches and banks, rather than full DX200 patterns.
To import a DX7 patch bank so that it shows up in the pop-up, just put the file in your Patch Base folder, under Modules > Yamaha DX200 > DX7 Banks. Similarly, you can import individual patch files by putting them in Modules > Yamaha DX200 > DX7 Patches.
You can edit the synth and rhythm sequences of your patterns in the sequence editors, controlling all of the parameters for every step. And to make some sequencing work faster, the bottom row of the sequence editors offer "link" checkboxes. When you edit a step that has its link checkbox checked, your edit will also apply to all other steps that are linked. This feature makes it easier to set the same drum sound for multiple steps at once, or change the tuning or velocity of several steps.