Add Rows Based On Found Row On Another Sheet

I want the code to insert a line under the row in which the code will find the value of the cell from an another sheet (there are two sheets - enter and base). If the code can't find the given value it should go to the last empty row in sheet and then perform some action (probably copy/paste job). Here is the code I came up with, the only thing I don't know is how to set the searched value as the A1 cell value of the sheet "enter" and what procedure to use in case this value is not found.

Sub findme()
'x is the A1 cell value in sheet enter
Workseets("base").Activate
Columns("B:B").Select
'if the following find procedure is successful
Selection.Find(What:=x, After:=ActiveCell, LookIn:=xlFormulas, LookAt _
:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, MatchCase:= _
False, SearchFormat:=False).Activate
'then
ActiveCell.Offset(1, 0).Activate .........