not sure this help or not

below are pretty basic simple stuff before you go

-bank statement and salary slip

-intention of going there ( very super important, it will determine whether u pass or failed like your fate, usually no problem if u have nothing to hide )

-address of hotel / resident

-Passport valid for travel to the United States

– Your passport must be valid for at least six months beyond your period of stay in the United States (unless exempt by country-specific agreements). Each individual who needs a visa must submit a separate application, including any family members listed in your passport.
-Non-immigrant Visa Application, Form DS-160 confirmation page.
–You will upload your photo while completing the online Form DS-160. If the photo upload fails, you must bring one printed photo in the format explained in the Photograph Requirements.
During interview

-some funny question will be asked by them , depending your visit

-it is video call btw , there are sometime got physicals appearance but from what i know now they use video call

-max 15 minute ,know as amercian 15 minute efficient cause a lot helang t20 rakyat cannot go on living without their phone ( yes the phone is put on a aside )
once u done the interview, the next few working day u will get the visa and start planing, huh , why oct , going for league of legend championship  ?
all the best

Of course can. Once inside, explain to the guy.

I accompany my mother. But the interviewer can speak mandarin. Anyway, I explain to her once my mother can't talk much.

Yup. Whole family.

If she able to speak mandarin, she can go in alone?