Setting field for portal row by same table in another layout
I'm sure a similar question is asked often, but I am absolutely stumped! I'm creating a database of recipes and their related costs. In one layout, the "Recipes" table contains a portal to "Recipe items". I'm tring to create a script that will allow the user to click on the"cost" field in the portal that will send them to another layout where they can search the databse for recipe and select any records they would like to accrue to their list of ingredients. i.e. like if you are making your own bread for a particular sandwich recipe. I've tried multiple methods using numerous global fields and "set field" scripts and variables, and I think I just have a poor understanding of correct sytax. How do I make the selected portal record a fixed field so that when the ingredient i.e. recipe is selected in another layour, it's RecipeID is copied into the correct Recipe and related portal row? I appreciate your help!