1. Yes you can connect 2 or more workbooks to 1 extract. All you gotta do is publish your extract to the Tableau Server and use it wherever need be.
Refer this link: Publishing an Extract to Tableau Online | Tableau Software
2. By automate do you refer to creation of extracts or their refresh of data?
Refer this link: Refresh Extracts
Hope this helps.
hi, want to refresh the extracts with tableau desktop
Depending on your IT infrastructure, for example if the tableau reader file is a live connection to a database connection, I believe reader will update when it loads. Alternately, you can load one or more datasets into tableau desktop, and create .twbx packages that can be distributed and interpreted by tableau reader.
tableau reader cannot connect to a live connection, only extracts, that why I want to automate the extracts
Oh yeah, I forgot about that bit. Tableau Desktop can connect live though so you can generate your extracts via that and then publish.
Unfortunately though, somebody will need to open the viz and select refresh all extracts before the tableau reader distribution will receive the updates.