I am in the directory where the files were downloaded, as per your intruction
BTW their is a typo on your instructions, you spelled bitmian instead of bitmain

I tried with and without the ./ in and out of the installation dir

Thanks for spotting that, I fixed the typo.
I am a bit unsure where you could be stuck or what could be missing.
Could you change into the bitmain-tools/scripts directory and try the following two commands and paste the output here:
ls -la
./l3plus_autotune.py
Generally, the more info you post, the easier is it to guide you through the procedure.