What constitutes a PUT, COPY, POST, LIST, GET, and SELECT for the Pricing Calculator?

You will need 2 pieces of information to correctly assign values and estimate costs on the Calculator: 1) what is the access pattern from your users (how many times they will be reading the data over a period of time like in a month), 2) how much data you will store (you already have this information).

PUT, COPY, POST, LIST requests for S3 are about write and list operations. For the data moving into S3 you can consider PUT operation in your case. POST is an alternate form of PUT that enables browser-based uploads as a way of putting objects in buckets. From what you have mentioned, it does not look like COPY operations would be relevant (read here about COPY). LIST request denotes all the requests to list objects and buckets - this is relevant for all listing operation to view the list of objects and buckets (not read or download them).

GET and SELECT are about retrieval/download (or more generally read operations). SELECT is a special case of querying the data using SQL like statements. Do not plan for SELECT as it is unavailable to new customers.

With that, based on what you have mentioned, I think you can create 2 records in Calculator for S3. One for the initial upload of 10TB of data (this should be mentioned in the PUT input). Another record for the monthly recurring 100-300GB per month data moving into S3 (also mentioned in the PUT input box). Add the number of requests you anticipate users will perform to view the list of files (add to the PUT and LIST input). And determine the download pattern and similarly add it to the GET input box. Please ensure you are selecting the appropriate storage class (S3 standard, S3 One Zone - IA etc.) at the top of the calculator.

Finally, even as you have setup your infrastructure, this blog could be referenced as a good example of how customers use on-premises File gateway using SMB, AD, and S3: https://aws.amazon.com/blogs/database/storing-sql-server-backups-in-amazon-s3-using-aws-storage-gateway/