I´m 43kg with 1.65m. Underweight and body type is Ectomorph.

my nutrition isnt really that good...
this is my plan that i am starting perhaps next week...
breakfast: soya milk, oatmeal & hard boiled egg
snack: sweet potato
lunch: whole meal (rice with tune/chicken breast with salad)
before-workout: protein drink
dinner: whole meal (rice with beef steak and salad)
before bed: milk

I would like to gain weight.

Ran thru some sites and was introduced to Whey Protein (like BSN Syntha-6) & Weight Gainer (BSN True-Mass).

What I have understand is...

1. Weight Gainer consist of both protein & carbs.

2. Protein whey is just protein.

My question is...

should i add weight gainer into my nutrition intake at the same time take protein whey only ¨before workout¨? or should I replace protein whey to weight gainer?