SSH into Docker container on DSM? - full N00b needs help with dockered linux game server on Synology DSM

Trying to set up a linux game server ( on a SYNOLOGY NAS. My DS918+ has an Intel x86 4-core CPU so that should be no problem in theory.
However using the official Synology Docker App I have some issues!
Registered, mounted and created a container of using Synology Docker GUI.
Successful Steam login and cs:go app download using the DSM Terminal built into the Synology Docker GUI. But cannot run server from there. Found out how to SSH into the Synology as root using Putty. But where do I go from there? Need to execute the commands that look like this:

docker run
-p 27015:27015/tcp
-p 27015:27015/udp
-p 27020:27020/udp
-p 27020:27020/tcp
-e “SERVER_HOSTNAME=hostname”
-e “SERVER_PASSWORD=password”
-e “RCON_PASSWORD=rconpassword”
-e “STEAM_ACCOUNT=gamelogintoken”

I am a linux / docker novice and only worked with Windows before. A game server Docker within a Windows Server VM on a Linux NAS would be far too stressfull for the hardware. The point why I want to run Docker on Linux is because the Synology NAS runs a custom Linux version. So Linux Docker containers would be executed directly from Kernel without additional performance hits. It shouldn’t be that hard to setup a “dockered” game server using precompiled docker images. Just need to find the path how to get to those containers/images starting from root@mynas.

Appreciate your help and sorry for the noob questions.

Info: Synology DS918+ (Intel Celeron J3455), DSM 6.2
Docker app v. 17.05.0-0395