Ask HN: How to manage developers who aren't very good?

Before becoming a team lead, I was the type of developer who, when given a task, would dig into the application api's, the database schema, the configuration, whatever it took to fill in the gaps to accomplish the task. Sure I'd get stumped sometimes, but I'd always try to ask for help sooner rather than later.

Now, I'm a lead of 4 developers. Two are like I was, I can give them a task, they'll go do it with minimal guidance. The other two will spend hugely more time on tasks. I've notice they tend to go off on tangents, spending time things that aren't relevant, like setting up vm envirnoments they don't need when they can develop and test locally. There have been occassions when they have asked me for help, and then a week later come back with the same question as though we had never talked about it.

It's baffling to me, it's like they're "scatterbrained", ie not focused or concentrated. How does one manage people like this?