Waveform averaging

Hello.

I have to acquire noisy sine signal (about 30 kHz) with NI PXI-5105 60 MS/s digitizer. I tried to make a VI using LabVIEW help but got the following result:

Apparently, it is necessary to make waveform averaging but I don't know how to do such a thing.

Here shows how signal is indicated:

I found here the following example from RavensFan, but could not use it:

There is a type mismatch:

Is there somewhere a detailed description of the LabVIEW's waveform / complex waveform / … data types with examples? I so stupid and standard LabVIEW help did not help me.

Thanks in advance for your help and sorry for my poor english.