VBA. Loop without Do. Can't get loops and if statements to work

I'm trying to loop through rows from 310 to end of the sheet (thousands of rows), and when cell in f column is empty i want to go trough rows that are two rows under the empty cell until the value of b column is not 2. If in these rows value of r is 100 i want to move the row below the initial row that started the for loop.

When trying to run it excel gives an compiling error: Loop without Do.

This is the first VBA script i have ever written. Familiar to other programming languages like python and java.

Sub moveConditionedRows()
Dim i As Long, j As Long, k As Long, l As Long

For i = 310 To Range("F" & Rows.Count).End(xlUp).Row
    If Cells(i, "F").Value = "" Then
        i = i + 2
        j = i - 1
        Do While Cells(i, "B").Value = "2"
            k = k + 1
            If Cells(i, "B").Value = Cells(j, "C") Then
                If Cells(i, "R").Value = "100" Then
                    Rows(i).Cut
                    Rows(i - k).Insert
            End If
        Loop
    End If
Next i
End Sub