[ubuntu] Dual boot windows 10 with Ubuntu on new Asus Core i3 Laptop

Good evening forum, I just purchased the Asus 2 in 1 13.3 Touchscreen Intel Core i3 6gb Memory 500GB Hard Drive-Black Hairline Laptop and I want to dual boot Windows 10 with Ubuntu. I have done this for years but this is my first (I Think you call it) UEFI and I have seen videos of installations and they all are confusing. I have Ubuntu on a flashdrive already and I used Unetbootin.

Question 1. Is using Unetbootin ok or do I have to use something else?

Question 2. Do I have to go and resize the partition in windows by freeing up space first or can I do it the old Fashioned way by just booting up from the flashdrive in Ubuntu and just choose Install alongside Windows and size it from there?

Question 3. I have seen them all go to systems in Windows and then disk management and then when you go to install, they are using Install alongside Windows and just clicking install after that but one video said that wasnt good to do it that way, Is that true?

Question 4. Once they resized the partiion in windows then they choose something else in Ubuntu installation, they went and added swap space and then they clicked windows boot efi I guess to override that with grub and then installed. Is that the best way.

Question 5. My conce is, If I have to retu this for a hardware problem and in fear of warranty not being upheld because I tinkered with the harddrive partition, can I just boot back into windows and do a recovery and will it erase all of the harddrive and reinstall windows 10 over the COMPLETE harddrive and it will erase Ubuntu and take the laptop back to the original windows 10 only?