I use this site:
https://www.thekitchn.com/how-to-make-sourdough-bread-224367, and I get good results using their method. Keeping it is simple, feed it equal parts flour and water each day, not much, 1/2 to 3/4 cup. You'll have to take some out when you get too much. Long term, you can put it in the fridge and feed it weekly. I've also spread starter out in a thin layer on parchment paper. I let it dry, then crumble it up. Bag it and put it in the freezer. I've had good results for up to a couple years.

The jar should have a cover. If you keep it in the fridge you'll only have to feed it once a week. I've forgotten about it for a couple months at a time, but it still comes back once I feed it and let it set out for a couple days. Which brings me to another point, take it out a few days before you want to make bread. Feed it daily once out of the fridge.
Here's another good site where she explains water to flour ratios and how it affects your bread. I found a lot of good information there:
https://truesourdough.com/beginner-sourdough-bread-full-guide-recipe/

I keep mine in the fridge.  Feed it once a week -  I use 15 grams of the starter, 20 grams of rye flour, 40 grams of unbleached all purpose flour, and 60 grams of water (well water, non-chlorinated).  Mix it up let rest on the counter for a few hours until it shows signs of life (bubbles) then tighten lid and put it in the refrigerator.

I save the starter I don't use in the feeding in a separate jar.  The discard makes great sourdough pancakes and waffles amongst other things.

Also, when I feed I completely empty the jar and clean it with hot water.  Less likely to leave any kind of mold or whatever left behind to grow.

When I was getting started The fresh loaf forums were a big help.  I also used Peter Reihnharts book 'the bread bakers apprentice'

Do this:

275 grams warm water (no chlorine)
500 grams starter (100% hydrated)
500 grams unbleached white all-purpose flour
20 grams kosher salt

Mix water, starter and flour then cover and let sit for 30 minutes. Add salt then kneed until stretchy. Stretch and fold four sides then cover and rest for 10 minutes. Repeat fold and rest three (3) times. After third time place in large bowl, cover and let rise at room temperature until size increases 1.5 to 2 times. About 3 to 4 hours. Remove from bowl.  Preform 1 more stretch and fold. Coat lightly with flour. Carefully place in heavily floured basket and cover. Let Rise at room temperature until size increases 1.5 to 2 times.

Preheat oven and 5 quart Dutch oven for 45 minutes at 500 degrees. Carefully remove dough from basket and place directly in Dutch oven flour side up. Cut slits in dough. Cover and cook at 500 degrees for 20 minutes. Remove lid, reduce oven temperature to 425 to 450 degrees and cook for another 30 minutes uncovered. Remove Dutch oven from oven then bread from Dutch oven and place on cooling rack to cool.

Get this:

Try this technique.

The bread I typically make (basic Tartine country bread)

Day 1, evening:
Start with 20 grams of hungry starter.  Add 50 grams AP flour, 50 grams whole wheat flour, 100 grams water.  Let this sit out overnight.  By morning, 12 hours or so, it's ready to make bread.

Day 2, Morning:
In my case I mix 850 grams AP, 150 grams whole weat, 700 grams water - no starter yet.  Let this mixture rest for an hour or so (autolyze).

After an hour mix in your starter, 50 grams of water, 20 grams fine sea salt (2% by flour weight).

Then I stretch and fold it every 1/2 hour for 2 hours, then split and form your loaves or boules.  I don't - I make the whole thing into a single boule.  So I will do a last stretch and fold, then let it finish proofing for another 1-1/2.  

At the end of this I do final forming, and plop it into a baneton brush a bit of oil on the top, cover with plastic wrap, and put it in the fridge until the next day.

Day 3, morning:
I preheat a large enameled cast iron Dutch oven to 450f, when it's preheated then I flip the baneton over onto a piece of parchment paper, and lift it into the Dutch oven.  Score it, put the lid on the Dutch oven, and into the oven at 450 for 20-25 minutes. After the 20/25 minutes are up remove the lid from the Dutch oven and continue to bake until internal Temps are about 202. Usually takes an hour total in my oven.

Then I set it on a rack to cool, and let it sit until the next day (day 4, morning) before cutting into it.

So it's like 4 days from deciding I need to make bread until I have bread to eat.  Not a lot of hands on time - but a fair amount of calender time.

How do I make new sourdough?  
I want to start my own... I don't want someone's janky old starter.

Really all you need to do is mix a bit wheat or rye flour and water.  Take a bit of it and add more flour and water to it every day.  There is enough wild yeast in rye flours to start a viable culture.

The risk is, until the culture develops its at risk from bad bacteria.  It could fail after a few days, or it might not.

To minimize the risk of failure, use unsweetened pineapple juice instead of water for the first week.

Do a Google search on unsweetened pineapple juice sourdough starter.  There's lots of info on it.  

Starter I'm using now is about 2 years old and was started this way.

You really don't have to feed it "every" day.

I keep a small mason jar in the fridge with my starter and feed it once a week (ish).  Feeding is 15 grams of starter, 20 grams rye flour, 40 grams ap, and 60 grams water.  Any starter not used in feeding goes into a second jar, un fed, and is used for pancakes when I accumulate enough.

That's a beautiful boule you got there!