The LOOKUP and XLOOKUP formulas in Benchling works in the same method as these features in Excel. The formulas search in a one-row or one-column range (known as a vector) for a value and returns a value from the same position in a second one-row or one-column range.
=XLOOKUP(lookup_value, lookup_vector, [result_vector])
For example, in the following table, the function XLOOKUP(3,A1:A5,B1:B5) should return the value Cell 3.
XLOOKUP will only return a value when an exact match is found for the value being looked up. LOOKUP on the other hand will return the closest available value if the exact match isn't found.