To start to find information use the FREE search tool at: https://familysearch.org/
It is best to enter RANGES in the YEAR fields, because the census data depends on the date enumerated.So if someone is born in 1892 - enter 1891 to 1893.If you are guessingenter 1880 to 1890 or a broader range.And marriage records often don't have the age/dob of the parties.
Once you get a list of hits - click on anyone of them and you will get a more detailed screen of the data.
Sometimes on the detail page, on the upper left in the box, you will have the option of 'view image' - click on that and you can see the actual census/birth/marriage/death document.If it says sign-in to see image - you can just join familysearch - all free, to see those.
Sometimes for 'view image' its only at a pay site, but many times it's free.
You can also SAVE any and all data in your own SOURCE FOLDER - if you join and are signed in, by clicking the letter 'C' on the upper right - which is a nice, new handy tool.
Good Luck https://familysearch.org/
U S Census, 1920 Clark, Wisconsin
SELFOliver HendricksonM 34y Wisconsin WIFEAmy Hendrickson F 37y Illinois SONArthur A Hendrickson M 5y Wisconsin DAUDoris E Hendrickson F 3y8m Wisconsin
U S Census, 1930 Warner Town, Clark, Wisconsin HeadOliver Hendrickson M 45 Wisconsin WifeAmy HendricksonF 37 Illinois SonArthur Hendrickson M 15 Wisconsin DauDoris Hendrickson F 12 Wisconsin SonHarold Hendrickson M 9 Wisconsin
U S Census, 1940 Warner Town, Clark, Wisconsin
HeadOliver Hendrickson M 54 Wisconsin WifeAmy HendricksonF 47 Illinois SonArthur A Hendrickson M 25 Wisconsin SonHarold O Hendrickson M 19 Wisconsin
U S Census, 1930Exeter, Rockingham, New Hampshire
HeadOscar J PearsonM 32 Illinois WifeJessie R Pearson F 34 Iowa SonJohn R Pearson M 6 New Hampshire DaughterBessie A Pearson F 4 New Hampshire
U S Census, 1940Exeter, Rockingham, New Hampshire
HeadOscar PearsonsM 42 Illinois WifeJessie Pearsons F 44 Iowa SonJohn Pearsons M 16 New Hampshire DaughterBessie Pearsons F 14 New Hampshire
U S Census, 1920, Clark, Wisconsin SELFAlbert Degan M 32y Wisconsin WIFEGertrude DeganF 25y Illinois DAUAlice Degan F 3y Wisconsin
US Census1940North Hampton, North Hampton Town, Rockingham, New Hampshire HeadAlbert Degan M 52 Wisconsin WifeGertrude DeganF 45 Illinois