gi is generated by a light so if you create a light like a spot and want some gi check the gi option in the render globals then you can adjust the number of photons and so on heres a link to a tut. https://www.3dtotal.com/team/Tutorial.../global_01.asp
https://www.3dtotal.com/team/tutorial...rofaneray1.asp

as for ambient occlusion in the render layers select everything in the scene and create a render layer right click on the layer and go to presets and select occulsion. but youll need to adjust the shader on the occlusion layer select the blue circle and the attribute editor will pop up click on the arrow next to the out colour and change the distance to 1