The decennial census data for 1841 to 1901 generally give family structure for this period - as Manx civil registration only came in 1877/8 there is considerable overlap with the IGI (which is almost comprehensive for the Island) which allows birthdates (assuming baptism closely followed birth) and marriage dates to be determined. (Brian Lawson's indices to burials and later civil registration also make it easier to find the correct information)
Prior to 1841 the key documents are the entries in the parish registers (transcribed in IGI) and the use of wills to disambiguate families sharing common names (property records are also useful) - such information will with a bit of luck get you back to mid to late 17th C - before this records get scarcer and except for one or two parishes the key parish registers are no longer extant before 1640.

Why not state what info you do have and see if anyone on the board can help.