Have a goal, a simple achievable one. Not simple as in easy, but simple as in not complex.
‘Write a novel’ is simple (not easy.)
‘Write 3000 words per week, or two chapters, every other week poetry counts as x2 word count, weekends don’t count, and each story submitted counts as an extra thousand words toward the goal’ or some such nonsense, is over complicated and confusing (though not necessarily hard.)
Once you have your simple goal, make a plan to achieve it.
What does writing a novel take? Come up with a simple, straightforward plan to reach your goal.
“If I write x words per day, my novel will be complete in x months.” Are both of these x’s acceptable to you? Can you write x words every day? Can you bear to wait x months? Once they are, bam, you’re on your way.
Once you’re on that path, each day will move you closer to your goal. All you have to do is start! (I know that’s not ALL you have to do, I’m being encouraging!)