In music theory, modulation is just another word for a key change. Key changes are common among many styles of music, including my own. There are different modulation charts to reference. Here’s one of them…
From the chart let’s use B minor to C minor as an example. You’ll notice that a good chord to use as a transition is a G Major Chord. (If you’re in the key of B minor the 6th degree is a major chord, in this case G Major.)
Now let’s use my own music as an example of that modulation…
So you’ll notice the song is in B minor and uses the VI chord (G Major chord) to transition into C minor. In fact it uses the root of the chord so you really don’t know if it’s a G major or G minor. All the more allowing it to easily modulate from one key to the next. In this case only a half step up.
Until next time practice using modulation charts to experiment changing from one key to the next.