Construct it as follows:
Make a table with 4 columns and 8 rows. The columns are x,y,z and F, that is, the inputs and the output of your expression. The rows are as many as the possible combinations of the inputs, that is, 2^3=8.
Each row represents a number from 0 to 7, and should be numbered with increasing order. For example, row number 0 has x=0,y=0 and z=0. Row number 5 has x=1, y=0 and z=1 (101 is the binary 5).
The last column should be filled with the result f(x,y,z) that corresponds to each row.
Can you post the build and post the truth table, before we move on to the circuit?
I am sure your textbook describes the construction of a truth table. Alternatively you can have a look here http://mathforum.org/library/drmath/view/70363.html or search a bit on youtube for some multimedia guides.