It depends on what version of Dataiku you are using. "using the website" is not descriptive enough since Dataiku runs on a browser on all versions so it's always "a website".
If you are using Dataiku hosted in the Cloud then you need to use the Launch Pad: https://launchpad-dku.app.dataiku.io/ and create a new Code Environment. Otherwise if you are hosting it yourself you go Administration => Code Envs and create a new Code Environment.
