firstly, it is কি and not কী. secondly, what you asked is answered in a grammar book so, do not expect anyone will type a complete grammar book here. You need to have basic knowledge of English else hire a teacher who is teaching fundamental English. যদি বুঝতে অসুবিধা হয় তাহলে বাংলায় বলবো ?

you can use a sentence by learning a sentence.Such as, i am a student and you can make a question putting this verb at the first of this sentence like as, am i a student? and you can make it as different tenses by changing this verb.So at first you need to make a good intention beyond of learning english then need to practice a lot.you must be able to overcome your fear.Don't be worried whether you are going to make mistake.Everybody should learn from his/her mistakes.It's not too bad to give suggessition.Thanks.

Every sentence has a noun and a verb. A noun is a person, place, or thing. A verb shows action or state of being. Learn some vocabulary words and verbs. You might start with a teacher who knows your language and English, or take a class to learn. Good luck.

আমিও তাই মনে করি :)