how find Cluster center in text

Hello to all
Sorry
I am a beginner at RapidMiner
I need to work with RapidMiner for the university project
I have a thousand reviews
I want to cluster with more important words by weighting
I did this process
But
Only the words weighed clustered
I want to make sentences based on these words clustered
But there is an error
Can anyone tell me what to do?
And
I want to find the center of the cluster
What is the word cluster center or sentence?
Does anyone know how?

Thanks a lot
Please help me