1: download symbolic-win-py-bundle-2.7.1.tar.gz from https://github.com/cbm755/octsympy/releases/tag/v2.7.1

2:place it on a foler with only english path, for example C:\

3: Open octave, go to the specific folder where your file is, and enter:pkg install symbolic-win-py-bundle-2.7.1.tar.gz

4:You are done, now you only need to write on your script :pkg load symbolic

5:Enjoy!

IF error occurs: https://github.com/cbm755/octsympy/issues/867