How do you put blue eyes white dragon into battle?

For blue eyes get Kaibaman Cause his effect is you can use him to summon blue eyes

Generally, it's not a good idea to play a card if you need to tributes, but Blue eyes has a lot of ways to get him out. Kidmodo dragon, Kaibaman, White stone of Ancients, and Ancient rules are all good cards to get blue eyes out.
Kidmodo can be gotten from Mokuba, and when you send it to the GY you special summon Blue eyes from hand.
Kaibaman is in the Card trader's regular stock, and you can tribute it to special summon blue eyes from hand.
White Stone of ancients is a UR card from the Lords of Shining Box, and when sen to the GY, special summons Blue Eyes from hand OR DECK.
Ancient Rules is a spell card you randomly get from Ranked Duels, and can special summon Blue Eyes form hand.
Hope that helps.

how many cards do you have to sacrifice to get the blue eyes white dragon

Kaiba man lets you special summon him

You need to sacrifice 2 monsters.

You need to sacrifice 2 cards currently on the field

Level 5-6 monsters need you to send 1 monster to the grave to summon. 7+ require 2.