Why are you using two tables for this?
Use one table and a field on that table for type of shirt.
So I can summarize the total of T Shirts, not the total of T Shirts and Polo Shirts. Or is there any tools for summarizing those records? I only found how to summarize, not with conditions
To summarize only T-shirts, perform a find for "T-shirt" in the Type field, then run your summary.
To summarize both, perform "Show All Records" then run your summary.
You will find it far easier in the long run to work within found sets of a single table than to work between two different tables.
You can also create a summary report that groups your records by type (such as type of shirt) and presents the desired sub-totals for each:
Here's a link to a simple tutorial on setting up summary reports that you may find useful:
Creating Filemaker Pro summary reports--Tutorial