Enable user to make something out of two blocks?

My aim is to check the players backpack to see if they have 2 required items, so I want to check their Backpack for item 1 and item 2 and then I want to make it so they can then click a button:

1. click a button
2. Check to see after click if they have the items needed
3. if they have take the required items and give them a different item that is supposedly made from the two items that have just been taken

I just need to know where to start as I'm finding it difficult to start to code the process.

Thanks for help in advance.

This is incredibly broad, but here:

• FindFirstChild for finding if something exists.
• MouseButton1Click for seeing when a button is clicked.

ive set the variables, : local humanoid = part.Parent:FindFirstChild("Humanoid") local Character=part.Parent local Name=Character.Name local Backpack=game.Players:findFirstChild(Name).Backpack

Now would I find the children of the backpack and check if they have the blocks and then activate the function if they have?