I am a ba’al teshuvah. I was raised in a reform congregation and my family not religious. I have a birth certificate from the hebrew organization of my parents affiliation that has my given hebrew name upon birth. It is Listed as Shmuel Yehoshua. It is curious to me as I did not know that a second hebrew name was given to a child and that in my thoughts only Shmuel is my hebrew name. Should I consider that Shmuel Yehoshua is my whole Hebrew name even in light that it was not from a conferred orthodox jewish community? This is curious and I have in my thoughts discounted the second name and assumed I will only be named by Shmuel. Thanks.
Your name given to you at birth by your parents [presumably by your circumcision] is in fact considered your Jewish name. In recent generations it has become a widespread practice to give two names, such as yours. You are not obligated to use this name commonly, but when you are called up to the Torah and for Jewish legal documents both name should be included.