I have to install Arch first to install other distros.
I recommend installing linux mint or ubuntu as your main os. they're so easy to install compared with Arch or Gentoo. Linux mint and ubuntu more or less instal themselves and they work right outs the box!
Then once you gotta solid distro like mint or ubuntu download a virtual box and use that to install more difficult distress like arch and gentoo n Slackware. that way you get practice and trust me it will also save you hours of your valuable time. If something goes wrong you can scrap it and reload a previously saved machine state in a virtual box.
If your having trouble creating a bootable usb stick they're are many good online guides for it.
If Arch is your first its maybe a jump into the deep end as a first main install, but I don't judge. Thats the beauty of linux there is so much choice but in my experience ive found it better to operate a stable solid distro for main install and mess about with other dittos using virtualisation (virtual box).
how is your installation going????? are you still having problems???? have you dual booted??? do you have another OS on your partition????
