I used the following sourdough recipe from King Arthur Flour. I struggled at first, but mainly because I wasn’t doing regular feedings every 12 hours. Once I did that I had a starter within four days. Also, I found that it was not critical to have unbleached flour. I got a vigorous starter using bleached flour.
Another note: for the first few days the starter really stunk. Then something changed and it started to smell great. I found that after I pulled a cup out for bread, I could just add another cup of flour and half cup of water (i do use filtered, not tap), then a week later I could revive the starter just fine.
Apparently if you are going to be away from your start for a long time you can just dry it out, save the chips. Unproven by me, but they say this method preserves the starter for eons.