Preliminary Remarks
There are two ways to write (and any mix between them): "pantsing" or "discovery writing" and "planning" or "outlining".
Pantsers, as the word implies, disover the story as they write it, navigating its development by feel, writing "by the seat of their pants". The problem with this approach is that the writer might later disover turns that make is necessary to adapt the earlier parts. Also, driven as these kind of writers are by following their ideas, their plots may not always have good tension or even contain plot holes. All this usually necessitates heavy or complete rewriting. One novelist (whose name I forget) said he just rewrote his whole novels several times until the result was satisfactory.
Outliners plan the story in as much detail as necessary to structure their story well and avoid any problems with consistency and plot progress. The problem with this approach is that writing often doesn't feel as exciting. But it usually doesn't require as much rewriting as pantsing does.
Some writers employ a mix of both techniques, planning out the rough movements of the story but leaving enough to discover.
Certain genres are so complex that they cannot be discovery-written. For example, a who-dunnit detective novel requires careful planning of what clues are revealed when, and an epic fantasy about court intrigue require careful planning of how the factions are related, when they work togther, when agains each other, what the effects are etc. If the structure of your story is very complex and multidimensional, planning is usually necessary. The more linear your story is and the more it follows the internal viewpoint of only one character, the more it lends itself to discovery writing.
How to Find Your Personal Way to Map Out a Timeline
If you want to plan your narrative, employ all the necessary tools. Use tables (for example in a spreadsheet) to list your characters and their traits. Draw a diagram to visualize the development of a character's emotions or a network map for the relationships between many players.
For a timeline, certain representations have been established, and there is software to help you with creating it. I recommend that you do a Google image search for "timeline", "timelines", "timeline software", "timeline graph", "timeline diagram" and similar search terms to see what comes up. Do not forget to search for "timeline writing" or "timeline author" and such. You will find graphs of timelines that some well-known authors have used for their work. I remember seeing one by J. K. Rowling for Harry Potter. This might inspire you. Scroll through the images and see what appeals to you and what fits your current idea of the timeline structure of your narrative.
Then sit down and try to draw the rough timelines of your tale on paper. Label (only) the important points. Play around with different kinds of representation to find the one that seems to fit your story best.
Then draw it out with all the necessary detail either on a large enough sheet of paper or buy the app that does that kind of graph. I prefer paper. To my way of drawing diagrams it is more flexible (most software cannot draw everything but is limited by its functionality while on paper I can have gaps and diverging or crossing lines or whatever I want). Also, I find drawing by hand on paper more satsifying, and I can think better on paper than in a software. But people are different, so maybe try out a software that appeals to you. Many offer a free trial period.
Note
Some things you say remind me of ADHD. If that is what you suffer from, you may want to learn about how to treat and live with ADHD as an adult. Structuring yourself is usually an important part of it, as well as observing and understanding your attention span and how to deal with distractions.
