Kia ora Abootaleb Safdari

You say:


This is my these: One can not make any sense of life without religion or spiritual beliefs  in its broadest meaning : satanism or Abrahamic Religions..
If he ( or she) can, explain it please.. How can he explain to himself death, the universe ... and in one word: big questions?

I disagree.  The need for a so-called meaning of Life, or as you say "make sense of life" seems a concept deriving from the Middle eastern Monotheistic traditions (Judaism, Islam and Christianity).  From the indigenous perspective life creates its own meanings.  Life just is - we give meaning to our life through our actions. (see, for instance, Burkhart, B. (2004). What Thales and Coyote Can Teach Us: An outline of American Indian Epistemology. In Modern American Indian Thought. A. Waters. Malden, Blackwell)  Burkhart says Life is a meaning-making activity.

Likewise Sam Keane (And I'm sorry, I can't reference this one - it's in a box in my garage) says;  "Do not ask the meaning of life - life asks the meaning of you". (I think it is in To An Unknown God)

So there are many ways to answer your "big questions" - and not just from an indigenous perspective, but also with a worldview of Naturalism and Existentialism. 

There are also a large number of Humanists who have no religious or spiritual beliefs who are very fulfilled and find much sense and meaning in their lives through their actions. 

And to a specific questions - how do you explain death?  Death is a natural part of the process of the material universe.  Rather ask:  How to you explain immortality (if it exists.)  It is immortality that is not natural. 

How do we explain the universe?  It just is and has always been (in a range of different forms).