Here's a few helpful tips to make your life a little easier as a ROM Hacker.
For Windows users, File Explorer hides file extensions by default. This will likely be a hassle for you throughout your ROM Hacking journey since you'll be dealing with many files of different types that will likely share the same file name so it is recommended to enable showing them.
This an option in File Explorer, in the "View" menu as of Windows 11, but if you are having trouble finding it just search the web for answers.
The baserom doesn't include one but it is incredibly useful to have a CHR editor on hand for editing or viewing graphics resources outside of Lunar Magic. The recommended editor is YY-CHR. It is a portable program with broad use, so save it somewhere you will always use it instead of within your hacking project.
Once you have a tile editor, it is also recommended that you set it up in Lunar Magic as the default Tile Editor. You can do this by opening "File → Graphics → Setup Tile Editor..." from the application menu to open the window seen below. Here, provide the full path to the YY-CHR executable and check the "Replace yychr.pal file with current palette" and "Set transparent colors to blue" options.
Once set up you will be able to use the "Edit" button as seen in Lunar Magic's "GFX Bypass" windows, as seen below, to jump right into editing a graphics file.