When I go to Korean restaurant
Hi ~~~ when I go to Korean restaurant then the staff will ask me how many people.
If I wanna reply 2 people , is = 두 명인데요 ??

and If I wanna order 2 짬뽕 + 1 탕수욕
or 1 짬뽕 + 1 짜장면 + 1 탕수욕
how to say these sentences respectively ..
I just know how to order one dishes like 짬뽕 주세요 .....

After that when I finish that I want to warp up and check how to say together?
I know 계산해 주세요 and 싸주세요 ... but how to say that together ...
Korean grammar is difficult T_T

Question

When I go to Korean restaurant
Hi ~~~  when I go to Korean restaurant then the staff will ask me how many people.
If I wanna reply 2 people  , is => 두 명인데요 ??

and If I wanna order  2 짬뽕 +  1 탕수욕   
                               or   1 짬뽕 +  1 짜장면 + 1 탕수욕 
how to say these sentences respectively .. 
I just know how to order one dishes like   짬뽕 주세요 .....

After that when I finish that I want to warp up and check how to say together?
I know 계산해 주세요 and  싸주세요 ... but how to say that together ...
Korean grammar is difficult T_T

Answer

Most of answers, you know correctly.
1. How many people.
  "두명인데요?" is okay but it's better to use "두명이에요."
2. Ordering menu
  You can use '몇개' or '몇인분' or '서수(ordinal number)'
  2짬뽕+1탕수육 => "짬뽕 두개랑 탕수육 하나 주세요."
  1짬뽕+1짜장면+1탕수육 => "짬뽕 하나, 짜장면 하나, 탕수육 1인분 주세요."
3. Wrap up and check.
  You know right. Just say it together.
  "여기 계산해주시고, 남은음식 싸주세요."