The Raspberry Pi can be accessed either by wifi or ethernet depending on your needs and setup . 

It is recommended to use ethernet but i find wifi acceptable with the airplay server I used . 

For Airplay to work with the projector, I used the RPiPlay project. 

You can find it here : 

https://github.com/FD-/RPiPlay

Use this command line to have all the optimisations during the compilation.

cmake --DCMAKE_CXX_FLAGS="-O3" --DCMAKE_C_FLAGS="-O3" .. 

I then used this command line to rotate the display and have it ready for the iphone : 

./rpiplay -n dlproj -vr rpi -r 90 

which means the airplay server is named "dlproj" and its display is rotated by 90° . 

Then you can just open your iphone (or iPad or even a mac) and use the display mirroring feature of it .