Installing the Website and eCommerce Modules
Everything in Odoo runs through modules; think of them as features you switch on when you need them. To build your store, you only need to install one. Log in to your Odoo account as an administrator. Go to the Apps section from the main menu and search for "Website." When it appears, click Install.

The Website module already includes eCommerce , so you don't need to search for a separate eCommerce module. One install covers both. Once it finishes, your dashboard will show the website app as an option. Click it. Odoo will walk you through a short setup guide, and at the end, clicking "Go to Website" will open your store editor for the first time.