I am new to this tool, using Version 18.104.22.1687, I would like to create a simple report with just 2 fields, Table_name and Comments How do i do this?
You'll have to use Find on the relational model to locate your tables. Then click on the Report button and in Templates section click Manage button. Create new custom report template, save it and close the dialog. Then in the Reports dialog select that template to generate the report.
next question is, is it possible to display just table with comments in the diagram?
Not that I know
You miss understood me. Do not try to create template from standard report generation dialog (File->Reports). Instead use search facility and create report from there.
All you have to do is create custom report template for filtered objects (tables for instance), containing desired columns.