Combining 2 Vectors for Diagonal Movement

I am trying to make a simple player movement script with rigid bodies, but I have hit quite a snag. I want the player to move in its own local z direction when I use the forward input, but also I want it to be able to strafe while moving. I am not sure how to produce this effect because every time I have tried, it only does one or the other.

Any help would be great. Thanks!

I figured it out. I was using if statements to trigger motion. You cannot use if statements for motion to be able to add the vectors together.