How to add a view inside a view? I have 2 groups of blocks in a view, I would like to join both of them in one view, showing the first block (I have the groups all linked one to the other).
I did download Views Field View but I can not manage the way to get it work, joining these 2 views.
The module 'Views Field View' that you have mentioned is very good imo. In order to use it, you have to edit a view A and add another existing view B as a field of view A. 

But this is as far as it gets, it does not facilitate a 'joining' of views of any sort, for that matter I think it would be better for you to rebuild a new view with relationships etc, if Views Field View is not adequate for you.