how do you adjust shift linkage

my 1998 323 is started jumping out of first gear every once in a while, now i am having trouble ingageing first gear unless at a complete stop. if you are at a complete stop and put in neutral let off the clutch and then depress the cluch and go back to first it will grind but only in first. my repair manual says it is "a worn or damaged shift linkage cable or incorrectly adjusted shift linkage cable" but it does not tell how to adjust it. some one please help!!!

you may have two problems,1,clutch ,2worn box.can,t realy see it being adjustment on gear shift.is the box full of oil?