Validation Of Textboxes In A Form

Im looking to have some data validation on the 3 text boxes of my form.
Text box 1 is Item name and i wish for that text box to only accept Text up to 30 characters.
Text box 3 is Product code and i wish for it to only accept 10 chracters max, the first two of which must be text and the last ones must be number. eg CA04124 or EK123456, there must be at least 2 numbers after the first two letters but no more than 6, there must be two letters before the numbers also.
Text box 4 is Price which i want to only accept number.

I understand the text box numbering isnt even, i dont know why not. Here is the code i am working with. Is the only way for this validation to be done by editting the code? If so i would be very grateful for someone to do this for me or tell me how to.

Private Sub CommandButton1_Click()
Dim LastRow As Object

Set LastRow = Sheet1.Range("a65536").End(xlUp)

LastRow.Offset(1, 0).Value = TextBox1.Text
LastRow.Offset(1, 1).Value = TextBox3.Text
LastRow.Offset(1, 2).Value = TextBox4.Text

MsgBox "One item added to Main Page"

response = MsgBox("Do you want to enter add another item?", _
vbYesNo)

If response = vbYes Then
TextBox1.Text = ""
TextBox3.Text = ""
TextBox4.Text = ""

TextBox1.SetFocus

Else
Unload Me
End If

End Sub