Are you using sdk for your development ? if yes which version of SDK ?
For docker based deployment you should be using SDK4.1 and if you are already using it, you don't have to do all these steps that you are trying.
Check this project here from the same tutorial: https://github.com/jpotts/alfresco-developer-series/tree/master/workflow/workflow-tutorial
Suppose you are creating your workflow in platform project e.g. https://github.com/jpotts/alfresco-developer-series/tree/master/workflow/workflow-tutorial/workflow-... ,
All you need to do is that execute run.bat/run.sh script.
It will launch all the containers with updated extensions locally on your docker desktop environment.
If you have a server setup that is not based on docker deployments, then you have to copy your platform-extensions (amps, jars) to the server under $TOMCAT_HOME/webapps/alfresco/WEB-INF/lib and share-extensions (amps, jars) under $TOMCAT_HOME/webapps/share/WEB-INF/lib
Note, that with this approach all your copied extensions will be lost if you terminate your containers.
These threads may also be helpful:
If your server is docker containers based, then i would suggest to make use of DockerFile and docker-compose.yml in combination and launch your server. It will build the updated images with your custom extensions and launch all the services as configured in docker-compose.yml.
Check the steps here if you want to persue DockerFile and docker-compose based approach:
(ACSCE, AWS SAA, Azure Admin)