C#m is one of those guitar chords that sounds scary until you see the chord chart. It is actually a very easy chord to play.
Here is an easy version of C#m that is very common. It is played as a simple barre chord in the Am shape on the 4th fret. The finger position for this C#m are: Bar the 4th fret from 1st string to 5th string, 3rd finger on the 6th fret 4th string, 4th finger on the 6th fret 3rd string, and second finger on the 5th fret 2nd string. Please see the diagram below.
Another common version of C sharp minor is this one that is played on the 9th fret in the Em shape as a barre chord.
This 3rd version of C#m can be played with or without the bass note on the 5th string. I have smaller hands and find it a tough stretch to get the c# on the 5th string. You can mute the string, or simply not play the 5th and 6th strings.
Up at the 6th fret you will find another version of this chord that has a little different color. These variations can help you to get more subtleties out of your guitar playing. Try this one out.
And lastly, we have this cool version played on the 9th fret that lets the open E string ring. It has a nice bassy sound.