Hey there Miguel!
It is actually possible to mass-select a large area of sprites and/or tiles in the editor! Enable Select mode (the green cursor inside the editor tools) and you can draw a square/rectangle, and move that selection around (even copy it when you hold Ctrl).
Optionally, you can also lock layers (press the lock button inside the layers menu) to prevent specific layers being affected by the selection.
Unfortunately we can't provide account support directly in the comments here, so if you have any problem setting up or updating your account, don't hesitate to reach out to us at levelsharesquare@gmail.com