Update DESCRIPTION.md

03 P1765 Baseline EVM Algorithms/DESCRIPTION.md

-This directory contains code files for the P1765 Reference EVM algorithm. Description of the files is given in the main document of the P1765 standard.
+This directory contains code files for the P1765 Baseline EVM algorithm. Description of the files is given in the document 'help_file_single_carrier.pdf' (Single carrier code) and 'help_file_OFDM.pdf' (OFDM code), respectively. For better understanding of the code structure, two explanation files are added:
 
-<text to be edited>
+* p1765_code_structure_singleCarrier_v2021.06.28.pdf
+* p1765_code_structure_ofdm_v2021.06.28.pdf
+
+Example calculation results calculated using different MATLAB/GNU Octave versions are enclosed.