If a young person enters the classical music field only for money, he is in the wrong profession.

For our convenience, let us see the graphic image of the above sentence.

The following picture can be drawn after drawing underlines under the z-nouns and circles on the prepositions.

In order to make it easily seen, take away the combination of a circle and an underline. We can get the following picture.

Now find the verb part and put a V-mark on the word. The front part of the sentence, that is preceding part of comma has a verb "enters". The remained part of the sentence has the verb "is". Draw V-mark on the two words.

Compare two V-marks. When you find two V-marks, there must be a word that functions connector. Put a cross-mark (X) on the word. As far as there is no coordinator, there must be a connector that should be marked in cross-mark. This is a subordinator which functions a service word without any definite meaning. In our sample sentence, the word "if" can be marked in cross.

We can see the following animation. Remind the whole process we have followed so far.