To get a single row back from a Search, you add :first item.
Although if you are doing this in a workflow, then you don't need to do this, as you can just refer to the Step's thing (e.g. result of Step 1's number).
Although "vlookup" isn't really how the Bubble database works, as we can link things using Bubble's fields which is much much easier. You may well be making life complicated for yourself with your data structure.