Hallo,
i'm a beginner bitcoin user 
i want to ask some questions to you old users.
1. As a beginner, what should I do first time?
2. How can i get
BTC?
3. Then, how can I make to redeem the BTC?
thanks for the answers

Greetings

As you are beginner you should read pinned topics in this board
https://bitcointalk.org/index.php?board=39.0 and there you will find answers to your all questions.
Don't be lazy, read forum for a while and when you really find something what is not already posted and asked then ask. There is no point in starting new topics with the same old questions over and over again.
Beginners and help section is not a only section gives more explanation about the bitcoin and altcoin related queries dude. There are various boards in the forum which is need learn all the tactics to earn money via bitcoin and other crypto currencies.
Beginners should learn about
Faucets earning
wallet usage
ICO investment
Trading platform
Exchanges used to convert the bitcoin to fiat
Signature campaign
Bounties