When you want something from other people, 'I'd like' is a very useful phrase, such as I'd like a beer, I'd like a cup tea, I'd like like a glass of wine, ...etc.

'I'd like' can be translated as '我想要' in Chinese. It is pronounced as 'wǒ xiǎng yào' in mandarin.

我 (wǒ), the third tone, means I, or me.
想 (xiǎng), the third tone, means want, would like, or think
要 (yào), the fourth tone, means want.

Since 想 (xiǎng) and 要 (yào) both have the meaning of want, you can simply say 我 要 (wǒ yào) without 想 (xiǎng). However, its less polite but not rude.

Want a cup of tea? Tea is 茶 （chá ），a cup of is 一杯 （yī bēi ), so a cup of tea is 一杯茶 （yī bēi chá).

Add what you learnt about I'd like, then you can say I'd like a cup of tea without any difficulty: 我想要一杯茶 -- wǒ xiǎng yào yī bēi chá