looking for step by step instructions for download, install, and activate, elements 2025

All the apps and bundles are at Elements Family. The buying process will guide the steps. You can Start here:

https://www.adobe.com/products/elements-family.html

@Izzy11201, Elements 2025 is activated through your Adobe account sign in.  Have you purchased it from Adobe?  If so, you should have received a download link via email.  If you can't find the email, you should be able to find a download link in the Products page of your Adobe account.  You may need to scroll down to the bottom of the page, because registered products are no longer listed in chronological order.

(@Peru Bob, Elements 2025 does not have a serial number to activate.) 

See here:

https://www.adobe.com/products/photoshop-elements/download-trial/get-started.html

Then: Help > Sign in and enter the serial number.