Not sure what you downloaded but Chartboost is very easy to get running.
Download the SDK from the Chartboost website: https://help.chartboost.com/downloads/ios
Unzip and put the Chartboost folder in your “proj.ios” folder (can be anywhere but I’m assuming you put it here in the “import” below).
In your AppDelegate.mm file, at the end of the “didFinishLaunchingWithOptions” function add the code:
////////////////////////////////////
// Chartboost
Chartboost *cb = [Chartboost sharedChartboost];
cb.appId = @"your app id from your chartboost account";
cb.appSignature = @"your app signature from your chartboost account";
// Begin a user session
[cb startSession];
// Show an interstitial
[cb showInterstitial];
Include the chartboost.h file: #import “…/Chartboost/Chartboost.h”
Drag the “Chartboost/libChartboost.a” into your project.