The Drop B tuning is mainly associated with metal genres. This tuning does two things to the guitar sound: it delivers much more bass and it gives possibilities to play chords like C sharp and B with open strings.
Here is how you tune the guitar: B F# B E G# C#. The drop B tunings deviate from the standard tuning on all six strings, but it helps you to know that the distance is three semi-tones on all strings except the 6th string (B), that is five semi-tones down from the standard E.
It is important that you turn the tuning pegs in a direction that decrease the string tension and not the opposite; otherwise, you could break the strings and possible damage the guitar.

1. B tuning (B standard tuning or Baritone tuning) is an alternate tuning for a six-string guitar with the strings tuned to B E A D F# B. It means, that you should tune your guitar two and a half.
2. Oct 10, 2016 Theoretical Implications of the B – A – D – G – B – E Tuning. The most significant change that comes with the B – A – D – G – B – E tuning is how we deal with power chords. In traditional standard and drop tunings, the most common power chord arrangements rely, almost exclusively, on the fifth interval.
3. Let’s walk through the differences between standard tuning and open G: In standard tuning, your six strings are tuned like this, in descending order, from lowest-toned string to the highest: E (1st and lowest string) A D G B E (6th and highest string) In open G tuning, your low E string is tuned down a full step to a low D.

Power chords

Guitars, however, are typically tuned in a series of ascending perfect fourths and a single major third. To be exact, from low to high, standard guitar tuning is EADGBE—three intervals of a fourth (low E to A, A to D and D to G), followed by a major third (G to B), followed by one more fourth (B to the high E).

Comment

As you can see from the diagrams, power chords with the bass on the lowest string can be played with one finger. The normal power chord shape is used when the root note are on other strings, as seen in the diagram example above that show A5.
Some other power chords in short notations:

C5: 111XXX / X688XX
D5: 333XXX / X81010XX
F5: 666XXX
G5: 888XXX / X133XX

Some other chord possibilities

Here is a collection of other chords that can be used in the Drop B tuning.

Chords

B Minor Chord Guitar Standard Tuning

B Standard Tuning Guitar

As you may notice, you can to a high degree handle the key of B as the key of D on a standard tuned guitar. The only exception is the 6th string.

Acoustic Guitar B Standard Tuning

This was an introduction about chords in the Drop B tuning, see also Drop C tuning.