I am new at SQL server. How should I start learning it.

Adding to Solution 1...

1. SQL Tutorial[^].
2. Welcome to SQLCourse.com![^].

I would have a read of these

A Beginner's Tutorial for Understanding ADO.NET[^]
Using ADO.NET for beginners[^]

and a good refernece site MSDN: Beginner guide to ADO.NET[^]

Create Data base on your own and create few tables inside it.

For better practice, create a simple application and Get values from the user from front end & those values to be stored in DB.

Try, Basic commands like Insert, Delete, Update.

w3schools is best site to learn, You can make use of it.