"How to Install Linux for the First Time Using a Portable Flash Drive"

I haven’t switched over from Windows yet but I plan on it, I’m just trying to find a good distro for beginners for one, and two, more of a question, what do I need to do with all my current data on my machine when switching to Linux? I’m assuming I’ll have to back it up on something else?

Is this stuff hard to learn ? . I have a old laptop and wanna do this

where i can find the full video?

How many gigs do I need on the usb ?

I would like to ask you, how may I get only the Command Line Interface edition of Linux. I want to lunch the Linux CLI directly from the USB. I don’t want to install Linux on my system’s SSD. What would you recommend? kali or anything better? Maybe you can provide a demonstration video please!