Bitcoin Forum

Is just download from the official website electrum.org and start using OK?

How many more things I need to take care of? Thanks!

You may want to verify your file signatures to make sure they are legit.

See this: https://bitcoinelectrum.com/how-to-verify-your-electrum-download/

and write down the seed words using pen and paper.

Additionally, don't save the seed in your email or cloud. It should never be shared online. Don't take pictures of it and keep it in your phone and don't store it in your computer, especially not un-encrypted and not password protected. You shouldn't save it to your computer at all but if you absolutely have to at least encrypt it.   

I agree with all other posters so far, but decided to make a checklist... Some of these points were already mentioned by previous posters!:

• Make sure you run an official version (check ThomasV's signature)
• Make sure you run the latest version
• Make sure to encrypt your wallet using a STRONG, UNIQUE password
• Write down the seed phrase, store it in a secure, OFFLINE way
• Never follow links shown by electrum or by any other source, if you need a new version, download it from the official website and check the signature
• A desktop wallet is used to store smaller amounts of funds... If you want more security, buy a hardware wallet, properly generate a paper wallet or do an airgapped setup
• Make sure your OS is squeeky clean... Don't install any financial tools (like wallet software) on a system running a cracked OS, or an OS on which you install unknown, or out of date software
• An OS (especially windows) NEEDS a virusscanner, an upgrade/update plan and a properly setup firewall

Next to this, there are things that are not specific to electrum (like keeping your OS clean) that are also worth mentioning... Like a native segwit wallet means lower transaction fees, enabling rbf is a good idear (especially if you cheap out on fees regularly) and anybody who has access to the seed,  the wallet file + passphrase OR the xprv (or individual derived private keys) has access to your funds,...

BTW, to be honest, i don't quite like the title of this topic... Electrum is still one of the more secure desktop wallets around. Sure, it has had it's share of vulnerability's (like most other wallets), but i would still recommand it to new users that are looking for an SPV HD wallet...