Keyboard - using the accent and character marks - if you press the Tilde (~) or the grave accent marks by themselves, the characters will appear on a space of their own. To get them to work the way they should press OPTION and the regular character indicated (simultaneously); then type the next character. (The one you want the accent to appear over.) (These accent marks won't appear over just any letter you type - it has to be one the Mac thinks makes sense.) (Tilde = OPTION-N then type an "n")
(Grave accent = OPTION-GRAVE ACCENT - lower case Tilde - then type an a, e, i, o or u.) (Acute accent = OPTION-E - then type a,e, i, o,u, or E. (Umlaut = OPTION-U - then type an a,e,,o,u, A,E,O,U.) (Cent sign
