Finally got this stuff. It takes weeks for delivery. I can wait to use it once I received my package yesterday. It is easy to use. Absolutely you can use it alone and anywhere. I can see my teeth become white, which might be my subjective feeling. I will keep using it and see what will happen with my teeth. Hopefully, this comment can help you guys.
This kit is very simple to use, it comes with a very easy guide to follow. I found the whitening treatment made a difference just after one use. My teeth also felt very clean afterwards. You don't need to use a full tube for both tiers, half of it or less is more than enough.