The soft consonants are palatalized, therefore closer to a 'y'-sound, but that 'y'-sound may not be an extra sound, that is, it melts together with the consonant. The ь implies, that you pronounce the consonant softly AND include a clear 'y'-sound.
So, if it was пёт, you'd pronounce p'ot (a palatalized p). But here it's пьёт, so it's pronounced p'yot (a palatalized p and a clear 'y'-sound).
Imagine a word пот, then you would say pot (not palatalized p! and no 'y'-sound). And there is a 'hard sign', which is ъ, and if you put that in like this: пъёт, it'd be pronounced pyot (a hard (non-palatalized) p followed by a full 'y'-sound).
Mostly context or additional words like "now". If you describe the situation when it is possible to mix these two forms I'll tell you what sentence would native use. Speaker is interested to be understood right so usually there is no misunderstanding. In some cases one can ask again "сейчас или вообще?" (now or in general?)