I can somehow buy bitcoins.
Yes. I suggest localbitcoins.com
Maybe with my bank
I doubt that your bank will sell you bitcoins, but you could use a wire transfer to get money from your bank to a bitcoin exchange such as BitStamp.
or even paypal
That's a very bad idea.
Then, I get something in my "wallet" whatever that is.
Well, first you have to actually get a bitcoin wallet. Here are some to look into. Learn a bit about the benefits and issues with each, then choose the one that best fist your needs:
- Paper Wallet
- Armory
- Bitcoin-Qt
- Electrum
- MultiBit
- blockchain.info/wallet
Some sort of code, or a string of characters?
The wallet will provide you with a list of bitcoin addresses that can be used to transfer bitcoin value to control of the wallet. A wallet can have one or more addresses. Each address will also have a private key associated with it which is used to transfer the bitcoin value to some other address when you spend/use it. Most wallets keep this private key hidden from you stored in a computer file. It is important to understand how to properly create a backup of the wallet you are using so that the private keys aren't permanently lost in the event of a computer problem. If the private keys are permanently lost, you permanently lose control of the bitcoins associated with the address.
Is that string of characters my "bitcoin" or my security?
The wallet will indicate to you how many bitcoins it has control of. The address is what you give out to people/companies so they can transfer bitcoins to your wallet. The hidden private key is what the wallet uses to transfer those bitcoins to other addresses when you use/spend them.
How do i keep my "wallet" safe?
That depends on the wallet you choose to use. In general:
You need to make sure that the private keys are not permanently lost. So be sure you understand how to properly create backups of the wallet, and remember to create those backups as frequently as needed.
You need to make sure that a thief doesn't gain access to the private keys. So be sure that you protect the wallet with a good password, and don't allow a virus or other malware to run on the computer that the wallet is installed on. Also make sure that the computer can't be hacked into over the internet.