Once you use part1.bat, the file you want to edit will be ExtractedRomFS\message\*Region*_*Language*\menu_msbt_LZ.bin
For me it was ExtractedRomFS\message\US_English\menu_msbt_LZ.bin
You'll want to download , then use Tools->Manage LZ11->Decompress on that file, which will produce a file called menu_msbt_LZ.bin.bin. You can then open that file using File->Open to start editing.
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Just as a note it contains ALL of the text in the homemenu, so you will have to search for what you want to edit as there is a lot