Welcome to STEEMIT @mahiahasnat. I thought to guide you a bit as you look like you are lost on that site and can't find the war to start.
So you should start by subscribing the Newcommer's Community.
And after joining that you should take a look at the link given below, there you can find how and where you should introduce yourself as it will be your Achievement 1 on the Newcomers community. Then the Greeters fairy will verify you are there then you can continue with whatever you were doing. Thanks