Here you can find some frequently asked questions about OST.
Post a /ost
comment on your patch in GitHub.
All non-OST patches can be tested posting the comment /ost in your GitHub patch.
When an OST run fails for your patch, you should see in the PR:
All checks have failed,
1 failing check'.
OST Failing after Xm
Click on 'Details'.
There you will find a link to the failing job with the job id. In that link, accessing the 'console output' would gain you some more information.