Where- is an adverb relating to place/ position.
I know where you left the bag.
मुझे पता है कि आपने बैग कहाँ छोड़ा था।
Were- is the plural tense of the verb 'are'.
We were playing outside.
हम बाहर खेल रहे थे।
We're- is a contraction of 'we are'
We're going to the park.
हम पार्क जा रहे हैं।
Wear- is used when talking about clothing.
I don't know what to wear.
मुझे नहीं पता कि क्या पहनना है।