Richelle,
You are on the right track - you have entered some information on the profile for Bernice. I suggest the following steps to build the full picture.
Enter what you have so far showing sources. - I have added a little with sources for both Bernice and Alvis.
The birth certificate is needed but it will not confirm that she is the same person that married Alvis, so more is needed. Do you have the death certificate for Bernice - who was the informant? Can you check with them?
As there are multiple marriages I suggest you try to find all of the marriage records and add them. Sometimes parents are listed and sometimes family members are witnesses. In addition to the two children listed were there other children? Did Bernice have any siblings? They need to be entered. Copies of divorce records can also be useful. Have you found them?
How many times were William and Louise married? Is it possible that William is a step-father? It is very common to find step-parents listed as parents especially if the child was quite young a the time of the parents second marriage. - If you build the data for William and Louise that may give a clue. So adding the census records with all of the siblings is important.
You will need to be very careful - as I'm sure you already know there are family files for Benice showing Sam Bass as the father and ones showing William Hodges - none of the family files seem to have solid sources - so you will need to dig. It might be useful to add the Sam Bass family profiles as well - not as parents but as another set of profiles - so you can add sources to both sets of profiles as you find material.
There are many examples on Wikitree of research - here is one with some detail showing how the profile was built and various marriages were found. Emmit Alexander Roach