installing windows 10 from iso image to sdd external drive

[Lucrarellovski]

I’m trying to install windows 10 from an ISO image to a new, blank 230GB SSD external drive. This drive is meant for my other laptop which cannot boot directly from it. However, the installation process now prompts me to "choose what to keep," even though this is a new drive.
My concern is whether this process will potentially wipe out all data on my C drive, as I need to keep everything intact.
How can the new external drive keep any files or apps if it’s blank?
Does this mean that windows is somehow attempting to reinstall the ISO on my existing C drive which is not what I want? This is very frustrating..

 

[Grizzly]

You are not installing on the external drive but your main drive instead. If I read this correctly, you want to use the installation on the external drive in another computer, correct?
The way you try to do will never work.
What you need to do is to put your ISO on a flash drive using RUFUS. then you can start the laptop from there and install on the previously installed new SSD. That is the only way...