Functional grammar is the study about corcerned with meaning. functional grammar also interested to analyze language at the text level rather than sentences. actually functional grammar is different with traditional grammar. you can find the component in functional grammar in this book.
find the Link bellow:
https://www.mediafire.com/file/apdj2v3ou9drc8f/v._Halliday__Matthiessen_-_Hallidays_Introduction_to_Functional_Grammar-1%5B1%5D.pdf/Halliday__Matthiessen_-_Hallidays_Introduction_to_Functional_Grammar-1%5B1%5D.pdf/file