Query in Dependent Hypothesis testing assignment

Hi team,
I had a query in hypothesis testing regarding the weight loss program assignment.

My query is how to decide when to put the 'g' and when to put 'L' in the t.test() function.

Also looking on the internet I found that we use p-value as it is for comparing with alpha when alternative hypothesis is having one-sided inequality of less than 0. Whereas we compare 1-p value with alpha when alternative hypothesis is having one-sided test and inequality is greater than 0.

If HA:μd<0HA:μd<0, use pt (t, df ). If HA:μd>0HA:μd>0, use 1 - pt(t, df). If HA:μd≠0HA:μd≠0, then find the p-value for HA:μd<0HA:μd<0, and multiply by 2.

source: 9.2: Paired Samples for Two Means - Statistics LibreTexts

Eager for your solution.
Thank you.
Best,
Yuvraj.