Assistants I create in the playground can be used in my code using its id.
The purpose of the interactive Assitant creation is to test before you code - it is a no-code UI to quickly build assistants and not to consume them other than an interactive test.
The interactive assistant is basically a wrapper over the API so it is as if you created in the API
Assistants can be accessed by an application you build making API calls to the OpenAI service endpoints, typically these apps make use of Node.js or Python in flask that reside on a virtual cloud server, but could be based anywhere.
Just go to https://platform.openai.com/assistants
You see the ‘robot’ icon. You can create the assistants here then test in the playground
by clicking the three dots to the right of the assistant name details.