I am trying to write an adapter to parse data from an mts file and I don't know where to start
the adapter should create virtual tables with the metadata and filter it whenever it recieves a SQL statement to do so.
the mts file raw data has keys for each attribute to tell what type it is.(" for strings, % for numbers ) .
This question is very vague and the commentators correctly point out, that there should be more preparation on the OP's end.
The best starting point for that preparation is checking the SAP documentation on developing your own adapters for SDI:
Data Provisioning Adapter SDK Guide
This documentation contains examples for how to build, install and use custom SDI adapters.