How use Merge Excel Document file

Have a look on the below link if that helps 

https://community.appian.com/b/appmarket/posts/excel-template-merge#:~:text=Excel%20Template%20Merge%20is%20a,depending%20on%20the%20use%20case.

How to install plugin ?

If I wanna convert file CSV to Excel, what is plugin I must install?

For plugin Installation https://docs.appian.com/suite/help/21.1/cp-10/cp-deployment-guide.html.

For converting CSV to Excel https://community.appian.com/b/appmarket/posts/csv-to-excel

If you want any plugin in future simply navigate to appmarket.

In your link, if i install plugin, I must do step by step like below?

Simply navigate to the admin console click on plugins from the side navigation and search for the plugin and click on add plugin search for the required plugin and click on deploy.

I added plugin

But I can not found it in process model

Smart service name is Generate excel from CSV not CSV to Excel. Please try to write Generate excel from CSV

I found it,

But I test it convert CSV to excel, it can't do it

I format like below

HC Altran _someid_page1 is your doc name?

it is file csv