I started out from a drawn-out tree on paper that I was provided with by an older member of the family (I later found out that there were many errors in it, so be careful not to believe all family tales!)
I worked, obviously, back from myself to parents, grandparents, and then I went back as far as I could in the paternal line, mostly because of that tree I'd been given, but also because it was an unusual surname, and located in a very small area. As Pennines suggested, I noted wives maiden names, and names and birthdates of siblings to the marriages, but didn't worry much about them until I felt - a couple of years later - that I'd got as far as I reasonably could on the "main line".
I then started on my paternal grandmother, and did the same.
Then I took my mother's father's line, until I fell into the Irish sea.
So I started my mother's mother's line. It took me a little longer there to splash into the Irish sea, but stopped there.
And then I started "filling in", mostly with families and ancestors of wives married in.
There's no real right or wrong way to do it - at one point, on someone's advice I built up a large collection of library catalogue like cards, one on each ancestor, even colour coded, but I've calmed down since then!
As I'm a largely visual person, I prefer to build a diagrammatic tree, in the good old fashioned way, but that's just the main bone structure. I have an online tree (or twelve), for different lines, rather than one huge one.
Don't feel overwhelmed. Most of us, especially at the early stages, feel we have too little information. The key is to sort it out so that it makes sense to YOU. Don't panic. You sound to have got further back than many people manage accurately, but you need to impose YOUR order on it.
Oh, and just one more thing:
It never ends!!
Welcome to insanity.
TY