Amiga @cintiamiranda21 You are missing basic points! 
What I am doing is feeding the node with the list of blocks that exist in the CAD file, viewing the preview and asking only the indexes of the blocks that interest me, it is a âmanualâ way of filtering, I do not know what criteria you want to use, and then I ask for the indexes of all the blocks with that name to: with that same index ask for the corresponding points of origin!
Also exist the dynamo hadboock and the dyccionary, You might want to take a look at it, there are some practical examples!
https://dictionary.dynamobim.com/#/Core/List/Action/GetItemAtIndex
https://dictionary.dynamobim.com/#/Core/List/Action/AllIndicesOf
Have a nice Weekend!!