Here’s how you can fill in the blanks:

(26) **How much** butter do you need?
(27) **How many** eggs will you buy?
(28) **a lot of** drinks in advance?

So the completed text would be:
"Plan your meals in advance. How many sandwiches are you going to make? How many loaves of bread will you need? Do you plan to make popcorn? (26) **How much** butter do you need? (27) **How many** eggs will you buy? Do you need to buy (28) **a lot of** drinks in advance?"