There are several options you may be interested in. First, getting your coins...
You will need to have a "wallet" for receiving BTC. That wallet is associated with "receiving addresses" that you give to a person who wants to send you money (BTC). There are various wallet options, this may help you decide. ( https://bitcoin.org/en/choose-your-wallet ) The main factor is whether or not you control the "private keys" for your wallet. You may never see them using bitcoin, and you should not show them to anyone. Hosted wallets are easy to use and great for a smart phone, however you are sharing your key and must trust the hosting website. I use an online wallet for convenience, but I keep only about $100 in it. Once you have a wallet set up and have provided a receiving address you can have your funds in mins.

If you want to sell them you are going to want to set up an account at an exchange in your country. There are a great many of them now. Look for a a legally registered business that practices KYC and AML. If they don't all you know for sure is that you are dealing with criminals and it could go very wrong. Exchanges can be linked to your bank account and make it super easy to convert to fiat. However, you may find it cheaper to just spend your coins. It saves a step and saves on fees. Over 100,000 places take BTC now and I only use bitcoin online and never "sell" it. You can buy anything now and it keeps growing every day.

The taxation on bitcoin is tax on "capitol gains". You pay a percentage on the appreciation in value, if any. You may also claim a loss if the price is lower than when you received them. So for example you get your bitcoin at a value of $220 but the price jumps to $260 when you go to sell them. Your then paying tax on the $40 you made. The rate varies from 0% to perhaps 15%. You will have to do your taxes to find out, but let's say it's 10%. You then have a tax burden of $4 to pay.

Hope this helps!