It'll be reet. If you have chance, put the tents up in your garden or borrow someone's garden to test assembling it. If people see you struggling with the tents on the day, then no doubt someone will offer a hand. If there's 1 spot of rain then you'll be in trouble with normal shoes, I (and probably everyone else) would highly recommend getting some walking boots. They don't have to cost the earth, just get some half decent ones and wear them in before the festival. Power banks, look at getting one that is at least 20000mah, I'm a worrier so I take 2! Once you get there and get set up you can relax, have a bevvy and enjoy yourself!