Help MCA analysis & clusters

Hello everyone,

I am trying to do the MCA analysis in order to get clustering on my data. (15 nominal variables & 150 observations)

The approach was to do MCA - Analyze> Dimenssion reduction> Optimal Scaling

Next, run the MCA analysis, I have the plot graph of points & graph of Object Points Labeled by casenumbers

My problem is following

I want to determine the number of clusters and the contents of each cluster

So, can you help me by (document, website, book, video-youtube ...)
to understand step by step this part on SPSS .....

Thanks in advance