Logs are available only using the command line at present (log web access is scheduled soon). First, you need to download the command-line.
Then, you must log-in using sqsc login, then you can access the logs using sqsc logs. Example of possible command-line invocations:
$ sqsc logs -f -project my-demo-project -container squarescale/sqsc-demo-worker
$ sqsc logs -project my-project-name
Just type sqsc logs -h to get help on the command-line.