Hi Oleksandr Tymokhin sorry i did not see your message earlier.
To become active delegate, you need:
- install lisk node on your server
- open an account, buy LISK and register as delegate (cost: 100 LISK)
- promote your delegate to get voted in the top 101
So far, the mainnet is not launched (scheduled for may 24th), so you can try on testnet.
You can pop in and ask on https://lisk.chat for more technical help and setup your delegate on testnet.