I think it's hard because of trying to manage yourself. Don't fixate on trying to "manage" your thoughts --- that is an active attaching and engaging with the thought in a way that's counterproductive to what one's usually seeking in meditation. Let them arrive as they do and don't attach to them or attach to the attachings to them, in that endless spiral of infinite fractalized jacob's ladders of connections of thoughts into new thoughts. Seeking to "manage" them is already attaching to them to do something active with them, and then it becomes much more difficult if not impossible to detach from them because it's like trying to throw something from your hand while your fingers are closed around it. Let them run their course passively, and experience what that feels like. If you're fidgeting or you're in pain, just notice it, don't try to manage it.

Just keep practicing. you'll notice that even as the thoughts form in your head and drift in front of your face and begin to branch, if you practice to not attach to them or "try" to do anything with them, they'll attach and build in that fractal way, but more weakly with less "coherence integrity", and the out-branching forms and shapes develop more hazily, and with less defined "ends" with which to keep connecting, and they will eventually become vague or faded and de-cohered enough without your "managing" that it becomes natural to let them float off on their way, out of your space-of-attention. kind of like if you've ever dissociated or spaced out, and sensory input kind of becomes "blurred;" where though you're aware of the presence of things in front of you or sounds or words being made/said, they have no coherent form that is gripping your active conscience and just kind of "happen" while you are there in a vacant state.

For me it kind of feels like that, but with that unfolding spiraling fractal construct of thoughts and feelings. They show up drifting in your face and you just kind of, mentally, with practice, become better at existing in a state comfortable with dissassociating from them, and that infinite-construct drifts from behind your eyes forward, and then moves from your face into the middle distance, as it grows and branches with less and less energy and its ends get blurrier and blurrier, and its forms get less and less descript and conspicuous, and at a certain point, it is blurry and nondescript or insignificant-in-detail enough to allow to pass from your awareness. Almost like happens when you're incredibly tired and slipping in and out of a hypnagognic about-to-fall-asleep state; where your thoughts get incoherent and blurred enough that it's much easier to let them slide by without gripping it because there's not much of significance to grip; you don't feel there is a "reason" to keep engaged with it, because it doesn't speak to or serve anything in your moment.

The more you do this the more comfortable you can become in the space observing your thoughts, and how it feels to be present with them without trying to "control" them.