Everything the plugin can do is in the documentation:
https://stephensherrardplugins.com/docs/pta-volunteer-sign-up-sheets-documentation/
Anything not currently in the plugin, that you would like considered, goes to the Feature Requests section here:
https://stephensherrardplugins.com/support/forum/feature-requests/pta-volunteer-sign-up-sheet-feature-requests/
This forum is for support requests only, please. Thanks!
Asking if the plugin can do something does not count as support, as there is already extensive documentation on what the plugin can do (plus, it’s free, so you can install it and give it a try).
So far, only one other person has asked for a CSV importer, which is not a simple task to do, due to the way this plugin has its data split across 3 tables (sheets, tasks, signups), so it’s not a direct 1:1 import type of operation. Just spent well over 100 hours on a major update to this plugin, and the available extensions. At this time, none of the extensions earn enough to cover my time spent on development, or the time I spend answering support questions (many of which could be answered by reading the documentation).
If there was enough interest in a CSV import, from people that would actually pay for it, I would consider it.