1920 census chicago ,school st
dobrenic, joseph owns house w/mortgage age 26 came here 1907, citizenship pending, born austria c&s ,language croatian, father and mother born austria/hungary, speak croatian, he is a laborer/machinist, and his wife is
Lina, 26 who came here 1912 is an alien, born same, parents born same, their kids b illinois
john 5 6/12; Joseph 3 10/12; paul 1 9/12; helen 5/12
1930 on shoal st chicago joseph age 40 now owns his house, he is a machine operator for elec co who came here 1905 from yugoslavia spoke croatian is an alien who married at age 24 to
caroline from slovenia in 1913, is naturalized who is 35 and married at 18, kids;john 15 who died 1966 and left spouse doris richards; joseph 14 a helper in a jewellery store, marries ruth, paul 12 marries blanche, helen 10, marries james ratliff, obit i sent you shows 2 more kids caroline or gertrude who marries james crowley and albert who marries phyllis. all the kids born illinois
your biggest problem is learning the border changes and if the city names changed as the countries did. i believe the area that they were from was austria before 1918. also, dont get too hung up on the ages, do approximates. eg sometimes a ship manifest will list someone a little younger than they were - under 18 was a cheaper ticket. sometimes a date of arrival is pushed back a little, or remembered incorrectly or the person made several trips. and sometimes people just plain resented the stranger at the door being nosy and asking personal questions. and sometimes people become younger as they age.
good idea to get some kind of computerized family tree program or, as many of us started out with, 3 ring binder with acid free archival plastic sleeves for copies of important documents. make a section for "unrelated" that is, those people with similar names and places of origin , destination, and residency. then, in the future, if you develop the genealogists obsession, you can prove that that is indeed your fathers brother, etc, took me four yrs to link one of my great great aunts to my great great g father but finally found her marriage record - and added a couple of dozen cousins.
if you cannot get to a library, you can ask for a census lookup - there are a lot of us out there who do not mind helping with the understanding that, someday, you will share your info and/or help someone else.
have fun