If statement for two values for large set of data - excel

Question

I struggle with VBA and have spent a few days trying to find a solution to this problem. Essentially, I have two spreadsheets with large sets of data. Column K of "Design Mods" worksheet contains the same types of values as Column C of the "Output" Worksheet. I've been trying to get my script to do the following:
1. for each cell in column k of "Design Mods", check if there is a matching cell in column c of the "output" spreadsheet
2. if a match is found, then populate the cell in "Design Mods" to columns over with the information from column b of "Output"
Because of my lack of experience, I've only been able to setup the script below which only checks and pulls correctly for one cell.
I need it to check each cell against a range of other cells.
Any help/guidance would be very much appreciated.
Thank you very much!
Sub MatchValue_Test()
'Routine is meant to populate columns "Design Mods" Spreadsheet with affected calculations from the "Output" Spreadsheet
'Variables below refer to Design Mods spreadsheet
Dim designmod As Worksheet '<-- Design Mods worksheet that we are comparing to the Output Data
Dim DesignMod_DClrow As Integer '<-- Variable used to count to the last low in the DC Number Column of Design Mods Spreadsheet
Dim designmoddc As Range '<-- Variable used to identify the range of values being checked in Design Mods is the DC Numbers Column K from K4 to the end of the column
Dim valuetofind As String '<-- DC Number used as matching criteria between Design Mods spreadsheet and Output Data
'Test Variables for integrating references to from Output worksheet
Dim testset As Worksheet
Dim test2_lrow As Integer
Dim test As Range
Dim valuetofindw2 As String
'Variables below pertain the routine itself
Dim found As Boolean '<-- this condition has to be false to start the routine
'Start of Routine
found = False
'Definition of Data Ranges in Design Mods spreadsheet
Set designmod = ActiveWorkbook.Worksheets("Sheet1")
DesignMod_DClrow = designmod.Range("K4").End(xlDown).Row
Set designmoddc = designmod.Range("K4:K" & DesignMod_DClrow)
'Test variables for integrating values from Output worksheet
Set testset = ActiveWorkbook.Worksheets("Sheet2")
test2_lrow = testset.Range("C2").End(xlDown).Row
Set test = testset.Range("C2:C" & test2_lrow)
'Identify the value being matched against
valuetofind = designmod.Range("L4").Value '<-- the script wont run if I have this value set to a range, and I need to figure out get this to loop so I don't need a variable for every cell im checking against
'test variables to figure out if statement
valuetofindw2 = testset.Range("C2").Value
valuetofindw3 = testset.Range("B2").Value
valuetofindw4 = designmod.Range("K4")
'If Statements performing the comparison
For Each Cell In designmoddc
If Cell.Value = valuetofindw3 Then
found = True
End If
Next
If found = True Then
designmoddc.Cells.Offset(0, 2).Value = testset.Range("B2")
End If
End Sub

Answer 1

You did not answer my clarification questions...
I prepared a solution, able to work very fast (using arrays). Please back-up your workbook, because the code will rewrite the matching cases in column M:M.
Sub MatchValue_TestArrays()
Dim designMod As Worksheet, lastRowD As Long, testSet As Worksheet, lastRowT As Long
Dim arrDes As Variant, arrTest As Variant, d As Long, t As Long, boolFound As Boolean
Set designMod = Worksheets("Sheet1")
Set testSet = Worksheets("Sheet2")
lastRowD = designMod.Range("K" & Cells.Rows.Count).End(xlUp).Row
lastRowT = testSet.Range("C" & Cells.Rows.Count).End(xlUp).Row
arrDes = designMod.Range("K4:M" & lastRowD).value 'load the range in array
arrTest = testSet.Range("B2:C" & lastRowT).value
For d = 1 To UBound(arrDes, 1)
For t = 1 To UBound(arrTest, 1)
If arrDes(d, 1) = arrTest(t, 2) Then
arrDes(d, 3) = arrTest(t, 1)'fill the array third column (M:M) with values of B:B testSheet...
Exit For
End If
Next t
Next d
designMod.Range("K4:M" & lastRowD).value = arrDes' Drop the modified array
End Sub
Try the updated code, please. It searches now for all occurrences and put each one in a consecutive column:
Sub MatchValue_TestArrays_Extended()
Dim designMod As Worksheet, lastRowD As Long, testSet As Worksheet, lastRowT As Long
Dim arrDes As Variant, arrTest As Variant, d As Long, t As Long, col As Long
Set designMod = Worksheets("Design") ' Worksheets("Sheet1")
Set testSet = Worksheets("TestS") ' Worksheets("Sheet2")
lastRowD = designMod.Range("K" & Cells.Rows.Count).End(xlUp).Row
lastRowT = testSet.Range("C" & Cells.Rows.Count).End(xlUp).Row
arrDes = designMod.Range("K4:AQ" & lastRowD).value
arrTest = testSet.Range("B2:C" & lastRowT).value
For d = 1 To UBound(arrDes, 1)
col = 3 'the column where the occurrence will be put
For t = 1 To UBound(arrTest, 1)
If arrDes(d, 1) = arrTest(t, 2) Then
arrDes(d, col) = arrTest(t, 1): col = col + 1
End If
Next t
Next d
designMod.Range("K4:AQ" & lastRowD).value = arrDes
End Sub

Answer 2

Using Match() is fast when your data is on a worksheet:
Sub MatchValue_Test()
Dim wsDesign As Worksheet, wsOut As Worksheet, m, c As Range
Set wsDesign = ActiveWorkbook.Worksheets("Sheet1")
Set wsOut = ActiveWorkbook.Worksheets("Sheet2")
For Each c In wsDesign.Range(wsDesign.Range("K4"), _
wsDesign.Cells(Rows.Count, "k").End(xlUp)).Cells
m = Application.Match(c.Value, wsOut.Columns("C"), 0)
If Not IsError(m) Then
'if Match() found a hit then m will be the row number on sheet2
c.Offset(0, 2).Value = wsOut.Cells(m, "B").Value
End If
Next c
End Sub