as a native Indonesian, maybe I can help you,
the usages of YANG, it depend on what do you want to say to someone.
some examples that you already found are correct.
*emphasis like "harga yang tinggi(= a high price)"
(It needs more examples)
Wanita yang cantik=a beautiful woman.
it shows that the woman is beautiful.
YANG is connecting the word WANITA=subject and CANTIK=adjective.
Anak yang pintar= a smart kid
Kaos yang besar= a big T-shirt
Koneksi internet yang lambat= a slow internet connection
# YANG in english can mean which, that.
Wanita cantik YANG berdiri di sana adalah istri saya.
A beautiful woman THAT/ standing over there is my wife.
wanita cantik YANG berdiri di sana = Subject
Surat yang kamu tulis padaku sangat menyiksa hatiku.
A letter that you wrote to me is really hurt my heart.
surat yang kamu tulis padaku= subject
YANG is showing that the word has speciality.
Wanita YANG CANTIK--> showing the woman is beautiful than the others.
wanita cantik YANG berdiri di sana-->pointing to the beautiful woman who standing over there.
*relatives like who, which, that..like
"Ini bukan apa yang saya tempah(=that's not what I ordered)"
(please give me more examples ^__^)
Ini bukan apa yang saya tempah(=that's not what I ordered
Ini bukan apa yang saya pesan.
TEMPAH is for formal situation but in Indonesia, we usually use PESAN to order something than TEMPAH. Sometimes people in Indonesia didn't know what is TEMPAH, so it's better to use PESAN.
Apa YANG kamu maksud? = What do you mean?
It need long explanation about YANG.
I just can explain like this, I hope my explanation will help you :)
If you need further information, I will help you.