This article explains how to create your Splash Page from scratch, assuming that you've already an SSID with Splash Page Editor (as here described How to create an SSID )
How to create a new Splash Page from scratch
In order to create a new splash page from scratch, please follow these steps.
STEP 1
In your Classic Hotspot Cloud Management, click on " WiFi SSID " then click on "Splash Page" tab
STEP 2
Click on "Edit Splash Page"

STEP 3
Click the arrow in the upper left corner

STEP 4
Click on CREATE NEW

STEP 5
From "start from scratch" Click on GO and start editing your new page.

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How to create a new splash page