Spline has an option to export your models into web content, which gives you a ZIP file with the files for a webpage to view your 3D model. However, the webpage allows you to view only the 3D model, and you usually want such cool stuff integrated into your website along with other HTML elements, rather than view the model alone with nothing else in the webpage.
Read the README for more details.
Use Alt + LClick to rotate the model. Click and drag your scroll wheel (or just simply scroll) to zoom in/out.