Categorical Variables

Hi, I'm an ultra-beginner to Stata and everything related to it. Nevertheless, I have to fix this problem.
I work on a large-scale assessment with 42,000 values. have 5 self-concept variables, one for each subject (eg: sskmat, sskdeu) and 5 grade variables, one for each subject (eg: tnotemat, tnotedeu) each with 6 grade characteristics (1 is bad; 6 very good) and the dummy variable female.

I basically in the first step just need two grade groups (German&Math High group and one Mathhigh group) and their respective self-concept mean for female and non-female. I z-standardized the variables as well but didn’t use it for this analysis so far, cause I needed the “real” grades (due to a lack of skills).

So far I managed it this way, but it’s not really convenient. I would also need a Cohen’s d (I guess?)

Mean sskmat if tnotemat>=5 & tnotedeu ==4 & female

Mean sskmat tnotemat>=5 & tnotedeu >=5 & female

How can I do this properly?

Thanks a million!!!