Option 1: In Classic Experience

• If you are in classic experience, which you can easily identify from the interface and from the presence of the Exit classic experience button in the bottom left, please press the Files tab on the top:

• Click New Document.
• Choose Site Page from the drop-down:

Option 2: In Modern Experience

• If you are in modern experience (which looks like in the screenshot below), please press the New button:

• Choose Site Page from the drop-down:

Further instructions applicable to both above-mentioned options:

• Create a page title right in the page header.
• Add some awesome content. To know how to add a ShortPoint web part, please click here.
• Press Save as draft or Publish.

Ready!
Now you have a beautiful modern page in a Classic SharePoint Site:

Thank you for your attention.

To learn how to install ShortPoint SPFx to be used in such pages, please check these articles.

To learn how to create a modern page on a modern site, please click here.