You can't tell. Though there are lists out there describing tastes...
There are very classic flavors, but *classic* flavors are expensive!
Bada--tends to be green, grassy, aromatic, does tend to have fruit returns. I tend to believe it's not the best of aging puerh, particularly for Banna.
Banzhang--several different profiles. What I consider to be Banzhang is a relatively menghai taste, closer to Hekai, Nannuo, and Pasha, with mushroom honey taste, a certain kind of floral aroma, that's a bit closer to Mengsong, Jingmai, Youle, but not as herbal/juniper like Nannuo/Pasha. Good tea will develop a sensate sweetness with a bit of age, will have a strong fruit return that's better than Bada or Mengsong, an active cooling and energy pattern in the mouth, stores flavors with coating astringency that slowly releases after the gulp. Much milder than the stereotype.
Banpen--less exciting version of Banzhang, so as I know. Less complexity. Guang Bien Lao Zhai is probably better tea, but gushu not commonly available--stronger honey-mushroom flavor, less fruit.
Jingmai--The point of Jingmai is a really complex aroma, probably the best puerh for aroma. This is not commonly available. Does have an unmistakable aroma in general, of a kind of dry, cloth feel, almost savory floral like lavender. Typically thought of as orchid, I suppose. The taste is relatively close to a good northern mengsong, but more floral and nutty. It should not have a strong sour-molasses nut taste if you're looking for quality. Tends to age into a weakly floral tasting hongcha.
Lao Man'E--medicinal bitterness, a very chocolate focused tea, even when young, fresh, and floral. Can have some similarity to Banzhang, but probably should be considered a Bulang
Mansa--this has a diverse amount of flavors. Does tend to have a sticky rice grain aroma. Broadly Yiwu flavors. Too diverse for meaningfull discussion.
Mengsong--strong and nice bitterness, tend to be thin like Bada. Menghai flavors like Nannuo, Pasha, Hekai, Banzhang. Strong tendency to have citrus notes in the taste from southern Mengsong teas. Bread, Brulee, or otherwise foodie notes in the aroma in the north. Tends to have good aftertaste with returning fruit.
Nannuo--distinct herbal aroma and taste that tends towards junipers or other conifers. Otherwise similar to Hekai, Pasha, and Banzhang. Not much for huigans.
Wuliang--tendency to have vegetal notes when fresh. Not usually worth your while to age as the flavor will thin. Will develop some nice fruit notes at first stage. Strong aroma.
Yibang--generic sheng base with strong fruit notes. Very slightly similar to worthwhile Jingmai, but not nutty. Not a fan of age in this tea. When it doesn't do hongcha, it tends to age into a honey taste with a sort of nice aromatic tar character. Relatively boring.
Yiwu--like Mansa, way too big and diverse, and comprises of areas that really should be separate identities.
Youle--think of it as a blend between a Jingmai, Yiwu, and Banzhang. Relatively fruity, but unlike Yibang, with a more meaty sheng base. Less lively and complex taste. Issue here is that there is really only one true Youle--at Longpa (the real thang, not "longpa"). There is mostly crap otherwise. This is relatively unusual since most tea areas have more than one village capable of delivering high quality maocha. Most Youle will have a strong one-note aroma, and most of them will age into mellow teas that aren't particularly exciting, but pleasant and sweet flavored.