To get started with Bubble Studio, you need to dump your app.db. To do this on 3.51 or below, send en e-mail to the e-mail account registered on your PS Vita containing the link email:send?attach=ur0:shell/db/app.db. (dot included). This will prompt to send an e-mail with your database attached, which you can easily send to yourself and open from your computer.
It is also possible to simply grab your app.db using molecularShell and HENkaku. However, since at the time of writing HENkaku has not been released (nor do I have a Vita on the required firmware version), I do not have instructions.
The interface consists of three major parts. First, we have the section with all available bubbles. Then, there is a toolbox pane in which editing options or instructions will appear. Lastly, there is also a menu with some core functions, such as adding bubbles, saving and an about option.
To start editing a bubble, simple click it. In the toolbox pane, editing options will appear. Here, you can change the bubble's icon, bootscreen and name. Icon and bootscreen paths are automatically generated but can be adjusted if desired.
When loading images into Bubble Studio, you will be presented with a cropper. To zoom in and out, use the slider or the scrollwheel. You can pan the image by dragging it. When you're happy with the result, press the button with the checkmark.
The launcher area is the screen which pops up when you touch a bubble. Using Bubble Studio, you can also edit its background. To access the launcher area editor, click the corresponding button in the toolbar (lowest one in the screenshot).
To edit the background, click the corresponding box. Please note that changing the image displayed in the startup gate is currently not enabled due to unsolvable issues. To return to the main editing pane, press button with the return arrow.
When you've finished editing a bubble, make sure to press the button with the checkmark. This will write the changes to the database.
If a bubble appears in the top row in the adjustment pane, it has been edited.
Adding new bubbles
To add a new bubble, press the "+ New bubble" option in the menu (top right-ish). This will open a pane on the right.
If you wish to add the Package Installer, select it from the dropdown and press the button with the '+' sign.
To add a "TheFlow PSone bubble", select it from the dropdown. Fill in the bubble name, title ID and settings title ID. You can also supply an image. Add the bubble using the '+' sign. If you wish to further customise the bubble, you can do so by using following the "Editing bubbles" part of this tutorial.
NOTE: I haven't been able to test this (my Vita is on 3.18, so I've got TN-X). It should work. I think?
Writing the changes back to the PS Vita
Press the 'Save' button in the menu to launch the save screen. Bubble Studio will now generate a new app.db and a savegame which will store your custom icons, bootscreens and launcher area backgrounds.
Pressing the first button with the database icon will save the modified database to your hard disk. The name of the file is already #0 for your convenience .
To write it back to your Vita, create a new e-mail on your computer with ur0:shell/db/app.db as the subject and attach the #0 file. Then send it to the e-mail account registered on your PS Vita.
To write it back to your Vita, change the name back to app.db and transfer it using molecularShell.
Pressing the second button with the trophy icon will save the savegame to your hard disk. To transfer it to your Vita, extract the archive and place it inside PSAVEDATA/<id>/bubblestudio. When you transfer it using CMA, the savegame will appear as PSP save data. Correct folder structure can be seen below.
After replacing the app.db and copying the save file, reboot your Vita.