Rename lang file into Lang Spanish 1.0
Open with Total Commander .

Edit file info.ini :
languagekey="spanish_1.0"
name="Spanish 1.0 by haplofeliz"
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Edit file i18n\Dictionary.lang and add (after you translated) at the end of file lines from the file atached.
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Warning :
- all lines from Dictinary must be like : xxxx="yyyy"
- delete all blank line after last translated line.