The first step in gathering your genealogy is to begin with your parents. What are their full names? Where were they born? What is their birthday? Document their family. Who were their parents and siblings? Births, deaths, marriages? These records are located in the counties where the events happened. Many records are now "online." For living relatives, start by talking to them directly. Often there are family records - for example, family trees might be recorded in Bibles, and some relatives may have begin collecting information on their own. For deceased relatives, many records are available from the website, https://www.findagrave.com/
Once you start stepping back generation after generation, you soon will see that the number of people who are your ancestors gets enormous very quickly. How many people could that be if there were 10 children in each family, and you can trace back 10 generations? Remember, your ancestors stretch out on both the mother's and father's side at every generation. By the time you go back 10 generations you have thousands of ancestors, and that only counts direct relatives. If you start to trace descendants of any of those ancestors, you start to encounter the 2nd, 3rd, 4th cousins, and the once, twice removed relatives, etc. Astronomical numbers folks. And all with a blood connection to you. Some have contributed their genes to you. Some have a common ancestor, so you and they have inherited from the same gene pool of your shared ancestor.
Sometimes people search only for their "direct" lineage, by which they usually mean their paternal ancestors. That way you are only looking at relatives that have the same surname as you. For example, if you wanted to trace your descendants from your 9th great grandfather, you would identify your 8th great grandfather, then, 7th, 6th, and so one until you got to your grandfather, and then your father, and finally you as the current or zero generation. If the hypothetical families were two parents and 10 children each generation (=12/family), then the total individuals in that descendant list would be 12x10 = 120 individuals. Subtract nine if you are an only child. But that would ignore the thousands of other equally significant relatives that come from every maternal link at every generation. And that of course, ignores all the marriages and families that happen with any siblings of your direct ancestor at each generation.
Could you do a descendant list following only your maternal lineage? Absolutely. Same number of direct descendants if the family size is as before. Those ancestors just wouldn't have your surname until the last generation with your father. Well, that's assuming naming convention was to take the father's last name with each marriage. That may be a law, but has been traditional. I understand some cultures assign surnames differently than our tradition, so the names can vary accordingly.
Want to document your ancestors? Just start doing it. Call your relatives and collect their information. Family Bibles sometimes record family tree information. County and cemetery records can help. And lots of online resources. Soon you'll be finding records from other people that fill in your ancestry.