Ok so i had the exact same issue never coded in my life, but this worked for me.
Hope this helps
Private Sub CheckBox4_Change()
'If user selects "Other" then TextBox4 becomes visible on the screen.
'It is intended that the user type in what corresponds to "Other" item in TextBox4
If CheckBox4.Value = "True" Then '"Other" is one of the selections from a drop
'down list present when clicking on CommandButton1
TextBox4.Value = "Please type in" 'instructs user to type in TextBox4
TextBox4.BackColor = &H80FFFF 'Highlights TextBox4 in yellow to alert
'user to type in it - this is optional code
TextBox4.SpecialEffect = 1 'makes TextBox4 appear sunken into screen
TextBox4.BorderStyle = 1 'Puts single line border around TextBox4
TextBox4.Locked = False 'unlocks TextBox4, which is usually locked,
'so user can type in it.
Else 'If user selects a selection other than "Other",
'or changed their mind after typing in text.
TextBox4.Value = "" 'Gets rid of any text the user may have
'typed in TextBox4
TextBox4.BackColor = &HFFFFFF 'Returns box to white color to make it
'blend back into white page
TextBox4.SpecialEffect = 0 'flat, not sunken in
TextBox4.BorderStyle = 0 'Gets rid of Single Line border around TextBox4
TextBox4.Locked = True 'Locks TextBox4, to prevent user from typing in it