Thank you so much to all who have responded to my questions it has been really helpful and comforting reading all your replies

Could you please explain to me in simple English how Bitcoin works?

Can you mine for Bitcoin and Ethereum on a single GPU rig at the same time?

How much does it cost to mine 1 Bitcoin (in the US)?

The 6 Biggest Risks to Bitcoin:

1. Bitcoin's blockchain loses its appeal
2. Brand-name businesses stop accepting bitcoin
3. A double-edged sword of regulation
4. A cyber attack hits Bitfinex (or another cryptocurrency exchange)
5. Margin mayhem derived from its CME listing
6. Investor emotions sack bitcoin

It depends on what type of wallet you are going to use. There are a few types of wallets:
1.Online Wallets(online exchanges, websites)
2.Mobile Wallets
3.Desktop Wallets
4.Hardware Wallets
5.Paper Wallets

Here are my recommendations:
1.Forget it!
2.Copay(very user friendly), Mycelium
3.Electrum
4.Ledger, Trezor
5.The thing with paper wallets is that it is more important how you generate them and how you keep them safe. Any tested paper wallet should do the work. Electrum for example could generate you a paper wallet.

What should I do with my Bitcoins? I have 420 BTC.

So what exactly is this “blockchain”?