"People" is plural, so the verb should be "celebrate," not "celebrates."
The correct sentence is "The people of Sindh celebrate Ajrak Day."
The word "attack" does not take any preposition.
The word attack is a verb which means کسی پر حملہ کرنا
Generally first form of verb is used with Did.
Generally, the word about is not used after discuss.
A relative pronoun is a word that introduces a dependent (or relative) clause and connects it to an independent clause.
The songs of new age sound bad to me means نئے زمانے کے گانے مجھے سننے میں برے لگتے ہیں
The subject of the sentence is "the death of the two stars", which is singular.
Therefore, the verb should also be singular.
The correct verb form is "was", not "were".
At a later date means بعد کی ایک تاریخ میں
The word like who, whom, whose, which, that etc. are called Relative Pronouns.