Start with the help that Marion pointed you to. It is easiest to start with a bullet (*) list after the references tag. You can also write a biography and cite sources inline (e.g., Alva Adkins and Ada Jeffers were married 23 Jul 1908 in Scott, Tennessee < ref > cite here < / ref>).
Once you have a profile, from the Name-#### menu, pick Research. This launches RootsSearch. You may need to login with your WikiTree login. From there you can search a number of places, but FamilySearch is a great place to start. Once you find a record on FamilySearch, you can just copy the section under Citing this Record as your bulleted item.
Sometimes you will find the person in the FamilySearch FamilyTree. This is a great clue for records, but beware that those are the correct records. For your searches, you might need to remove mother (or wife's) maiden name to get more results, and also the death info.
I tried this for Alva Adkins-6709. Oh the 1900 census is very interesting. Here are a couple for Alva:
"United States Census, 1900," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MSZS-6G3 : accessed 11 October 2020), Alva Adkins in household of Henry Adkins Sr., Civil Districts 6-7, Scott, Tennessee, United States; citing enumeration district (ED) 130, sheet 18A, family 289, NARA microfilm publication T623 (Washington, D.C.: National Archives and Records Administration, 1972.); FHL microfilm 1,241,595.
"Tennessee Marriages, 1796-1950", database, FamilySearch (https://familysearch.org/ark:/61903/1:1:X8RG-ZQV : 27 January 2020), Alva Adkins, 1908.
"United States World War I Draft Registration Cards, 1917-1918", database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:KZ6G-PKR : 24 August 2019), Alna Adkins, 1917-1918.
* "United States Census, 1940," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:K4ZP-618 : 26 November 2019), Alva Adkins, Civil District 3, Scott, Tennessee, United States; citing enumeration district (ED) 76-5, sheet 19B, line 42, family 316, Sixteenth Census of the United States, 1940, NARA digital publication T627. Records of the Bureau of the Census, 1790 - 2007, RG 29. Washington, D.C.: National Archives and Records Administration, 2012, roll 3932.