This might not really be the answer you're looking for. But my advice in general when people ask these questions is firstly you should learn as much as you can about what you like about music and what you dislike. Nerd out hard about the artists that you really like. Learn the chords, rhythms and melody types they use.
Copy those and alter them in your music. Learn what equipment they use and try to get the same guitar sounds or synth, try plugin emulations of amplifiers, recording equipment they used and replicate the chains.
Follow this path and steal and copy relentlessly.
Nerd out as much as possible.
Eventually you will find what you like about music and more specifically what you do or DONT like about certain chord progressions, rhythms and melodies and the aesthetic side and what compressors, preamps, guitar amps, synths, sample packs you do or dont like.
Maybe you dont even like compression and prefer lots of layers of saturation to tame transients.
You may wind up not liking the tools your favourite artists use when you sit to write music your music.
You may keep some stuff and throw out other stuff.
This is a long journey to find what you like about music and more specifically what you like to include and exclude which is just as important. It takes a long time to really hone in and you have to make mistakes and go down paths that dont work.
But once you know more about what you like about writing music, for your music, finding ways to start is easier because theres a long list of things you simply dont do with your music as youve discounted it as something you dont like in music.
Youve narrowed your bandwidth and work within specific parameters.
This isnt limiting but can be quite the opposite.
You have a box to be very creative in.
You might have a few boxes you like to use of different genres or styles.
For example you might like ambient techno dorian scale melodies with slow changing pad chords done in the box with plugins.
Or you might like psychedelic 60s recording using the correct vintage amps and preamps with beatles type harmonies but with large in your face fuzz bass?
You might do one better though, or you might do one for years and then realise krautrock is your jam now.
Nobody can answer this except you and you need to search for it in a few directions.
But learning what you dont like, and what to exclude from your music in general makes starting and finding ways to start a lot easier as you dont have a million options when you sit down.
SHORT ANSWER: Best way to start for me though is usually just ripoff a chord progression or a beat and make new music to it. Ha ha

Awesome Jake, thats the way! I just would like to add something from my perspective.

What helped me getting startet: Dont waste your time browsing gear, vsts and samples and looking for Quick-Fixes and stuff.
Learn to play the keyboard. If you do. Learn a few VSTs by heart. Get into sound design. Learn how to program synths and beats. Learn to record, fix and chop vocals.
Limit yourself and try to make a songcover using only one synth. Learn Music Theory, time measures and harmonies. Make alot of music and dont expect it to sound good. It will sound horrible when compared to the pros. And when you made something that sounds at least okay, get feedback from a pro.
How to getting started depends alot on your musical background. Start from where you are and learn what you need to learn to do the things you want to do. And in my opinion spend money on knowledge first on gear second.