You will need one form with record source written in SQL, like this:

SELECT * FROM myTable

Then create another form and put existing form as subform.

You also need one text box to enter search criteria. When you have
this form created you need to code AfterUpdate event of Text Box. For
simple filter you can code AfterUpdate event like this:

dim strWhere As String
strWhere = strWhere & " [myTableFieldName] LIKE ' " & myFormFieldName
& "'"

or, when filtering numbers:

strWhere = strWhere & " [myTableFieldName] = " & myFormFieldName

To have it filtered by multiply entries delimited with comma, code
needs to loop through string and it needs to repeat above command like
this:

strWhere = strWhere & " [myTableFieldName] LIKE ' " & myFormFieldName
& "' OR "
If Right(strWhere, 4) = " OR " Then
 strWhere = Left(strWhere, Len(strWhere)-3)
End If
mySubformName.RecordSource = mySubformName.RecordSource & strWhere
mySubformName.Requery

Basically you need to find the position of comma (,) with InStr
command and remember position of last found comma and simply loop
through string until there are no more commas, i.e.

instr(1, "text, text2", ",")

will return 5.

Let me know if you have trouble with code so I will wrote it for you.

Regards,
Branislav Mihaljev
Microsoft Access MVP