How to differ 想 and 要？what differences between them？

想 xiǎng & 要 yào
•for the meaning of 想,想has three meanings,the first meaning is want to do something,the second meaning is to think,and the third meaning is to miss.
e.g.1：我想买一杯咖啡
e.g.2：让我想一想
e.g.3：我想我妈妈
•For the meaning of 要,we also have three meanings,the first meaning is want something,the second meaning is need,and the third meaning is会,probably will.
e.g.1：我要/要买一杯咖啡
e.g.2：我要去上班，没时间看电影
e.g.3：我下个月要去中国
•for the pattern,if we use 想，then we have to put verb after,and for 要，we can put noun or verb,both of fine.

想 (xiǎng) and 要 (yào) can both mean “want”. However, they each have additional meanings associated with them.
想 can mean “to miss” when followed by a noun.
要 can mean “going to (do something)” or “want to”.
想 AND 要 FOLLOWED BY A NOUN
Both 想 (xiǎng) and 要 (yào) can be followed by a noun but mean different things. Let’s have a look at them separately:
要 with a noun
要 (yào) followed by a noun is normally used for commands like when you want to buy something or to order food.
PATTERN
Subject + 要 + Noun
Your tone when using this structure is very important because it can come off as impolite.
For visual learners, imagine a child having an outburst saying, “我要妈妈! 我要妈妈!” (wǒ yào mā ma! wǒ yào mā ma!) (I want my mother! I want my mother!).
This child’s tone is usually demanding and somewhat impolite.
我要茶。wǒ yào chá. wǒ yào chá. I want tea. (ordering at a restaurant)
你们要不要米饭？ nǐmen yào bu yào mǐfàn? Do you want rice?
谢谢，我什么都不要。 xièxiè, wǒ shénme dōu bú yào. Thank you, I don’t want/need anything.
想 with a noun
想 (xiǎng) followed by a noun is normally used for expressing the fact of missing something, or someone.
In the structure: Subject + 想 + Noun
想 means “to miss”
我想你。 wǒ xiǎng nǐ. I miss you.
我女朋友回国了，我很想她。 wǒ nǚ péngyou huí guó le, wǒ hěn xiǎng tā. My girlfriend returned home. I miss her very much.
你回美国以后，会想中国菜吗? nǐ huí měiguó yǐhòu, huì xiǎng zhōngguó cài ma? Will you miss Chinese food after you go back to the USA?
想 AND 要 FOLLOWED BY A VERB
When followed by a verb, 想 and 要 have similar meanings.
However, 要 shows more urgency and is at times more demanding while 想 is a bit more polite.
In this structure, think of 要 as “want to” and 想 as “would like to”.
要 as “want to”
PATTERN
Subject + 要 + Verb
Like the previous structure of 要 (yào), one’s tone is very important.
我要休息。 wǒ yào xiūxi. I want to rest.
我要喝咖啡。 wǒ yào hē kāfēi. I want to drink coffee.
你们要不要出去吃? nǐmen yào bu yào chūqù chī? Do you want to go out to eat?
想 as “would like to”
PATTERN
Subject + 想 + Verb
你想去吗? nǐ xiǎng qù ma? Would you like to go?
我想跟他看电影。 wǒ xiǎng gēn tā kàn diànyǐng. I would like to watch a movie with him.
他不想回家吗？ tā bùxiǎng huí jiā ma? Doesn’t he want to go home?
EXPRESSING “GOING TO” WITH 要
Here, 要 (yào) is used to indicate plans for the near future.
想 (xiǎng) can’t be used in this way.
CHINESE PINYIN ENGLISH
P星期六，我要去北京。 xīngqīliù, wǒ yào qù běijīng. I have to go to Beijing on Saturday.
毕业以后，你要跟父母住在一起吗？ bìyè yǐhòu, nǐ yào gēn fùmǔ zhù zài yīqǐ ma? Are you going to live together with your parents after graduation?
个月，她要找新工作。 xià gè yuè, tā yào zhǎo xīn gōngzuò. She is going to look for a new job next month.
EXPRESSING “TO WANT” WITH 想要
When the two characters are combined, they mean “to want”.
Nouns or verbs can be used after 想要.
PATTERN
Subject + 想要 + Noun/Verb
你想要什么礼物? nǐ xiǎng yào shénme lǐwù? What gift do you want?
她想要找一个有钱的男朋友. tā xiǎng yào zhǎo yīgè yǒu qián de nán péngyou. She wants to find a rich boyfriend.
他想要帮你找一个更好的工作. tā xiǎng yào bāng nǐ zhǎo yīgè gèng hǎo de gōngzuò. He wants to help you find a better job.

“想” mainly refers to mental activities such as having ideas, considering, or missing someone. For example, "I think about going for a walk.我想去散步。I miss my mum. 我想妈妈。
"要" indicates a desire or need. For instance, "I want an apple.我要一个苹果。
The main difference is that "想" focuses more on the mental process, while "要" emphasizes the desire or requirement.
let me have a thought. 让我想想。I got an idea.我想到一个主意。
i have a desire to go home 我想回家。i want to go home. 我要回家。
maybe you can show me the text that confused u.

It's a good question. “想”: Expresses subjective wishes or thoughts, with a gentle, uncertain tone. “想” typically corresponds to English "want to" (want to do something), "would like to" (more polite), "feel like" (feel like doing), or "am thinking about" (considering). “要”: Expresses strong intention or need, with a firm, decisive tone. “要” typically corresponds to English "want" (strongly want), "need" (need), "must" (must), or "am going to" (definite plan).

想表示你主观意愿，你的愿望，比如“我想成为一名歌手”“我想吃蛋糕”。要表示你将要做某事。“我要吃饭了”、“我要睡觉了，我们明天再说”“我要好好学中文”

想 is want, only mentally
要 is require， need， I will do something to get it.

想：主观上，需求性百分比的话，可能低于50%。
要：客观上，需求性百分比的话，可能高于50%。

Try to help you in three sentences:
1、wǒ xiǎng mā mā ， tā jǐ diǎn huí jiā ？我想妈妈，她几点回家？
2、wǒ yào mā mā ， bù yào bà bà 。我要妈妈，不要爸爸。
3、wǒ xiǎng yào yī bēi kā fēi 。我想要一杯咖啡。