Consider 2 random variables with their prob function given below?

I have an exam coming up and this is a sample question. It reads "Consider 2 Random Variables with their probability functions given below: Find the PDF(probability density function) and mean and variance of sum of X & Y. (The x has a line over and under it while the y has one line over it)

The table is

X| P(x)
2 | .4
4 | .3
8 | .2
9 | .1

Y | P
3 | .3
6 | .4
9 | .3

Can anyone help me with this? I've looked in my text book but it doesn't really explain step by step on what to do.