Windows 10 setup?

So I choose the language after plugging my Flashdrive with windows in and then I get asked about a product code I say I don’t have one then it asks me about versions I pick win10 home then I accept the TOS click “custom” as opposed to upgrade

Then I pick a place to download it I pick my 2tb HDD as I don’t have an ssd then I It says it’s downloading I wait then when it’s done It tells me it’s going to restart my pc so it does and then I’m back at step 1 except

That when I try to download it unto my HDD it(my hdd) has a partition and I can’t fix that without completely shutting off my pc and booting from USB AGAIN then it does the exact same thing

What do I do!? I just want to play age of empires 3 for gods sake