what makes your life happy if you have no relative?
There are periods that almost all people go through when Life appears meaningless.
During such periods even family and friends hold little interest. Such a moment is an invitation to seek knowledge. Some will pursue knowledge more deeply than others. Some will become caught up in the search for emotional comfort that is often derived from friends or, as you mention here, "family".
I did not have much family myself, having been raised in a Children's Home commonly referred to as an "orphanage".
Just the same, whether one has a family relationship or none at all, feelings of alienation can be equally strong for anyone. Strong feelings of being distanced from others can be a steppingstone to knowledge, or, a person can merely wallow in self-pity, if that is their inclination also. The point being that life, and the pursuit of meaning in life, can be a powerful source of motivation.
There are powerful questions, and these are universal. For example:
Why are we here? Who am I? Where and How did it all begin? What is Right and Wrong?
Should I care or not care?
To state an answer simply, as a guide that will serve some purpose, many have found somemeaning in the performance of Duty. One can serve either a Person that one respects, or one can serve an Idea. Whatever one can determine as the Highest Good, that becomes one's Meaning.
Talking with others, or the study of books and ideas, can also be a part of the search.
I have always found the writings of Omar Khayyam in "The Rubiyat" to be very informative in such matters. Beyond that, one can search at Law, at Theology, Science and Philosophy for some understanding of meaning. Another general guide would just be the general maxim that one should love others in the same way that you would want them to love you.
I think play sports with my friends
make a friend.
I think meaningless.