In the first place, you should be creating the Individual Portfolio items using the BE Grid custom post type. The detailed explanation about this post type and how to create a Portfolio item is given in this article. If you have created your posts already, you can move on to the next step.
Edit the page on which you want to add the Portfolio Grid using Tatsu.
In the left panel of the Tatsu Page Builder, navigate to the module list and search for Portfolio. Add the module in your page.
Once you have chosen the Portfolio module, the settings window will open, which you can modify the settings, accordingly.
If you would like the Portfolio to expand to the full width of the screen, edit the ROW enclosing the Portfolio module in the page builder and select the FULL ROW option.