Every writer has their own way of building their story, be it pants-ing (plotting as you go) or outlining. Over time I developed a way that works best for me, but it doesn't necessarily mean it’s the best way for you.
For my process, I take note-cards and write down all the events I want to happen in the story. When everything is written out, I order them in a sequential way that makes sense to me.
The next step is to link the events together. One of the tips I have tried to adopt to do this is the ‘but/therefore’ rule. I have added a link below with a video explaining the rule in detail.
If I get stuck, I read a book, watch a movie, or a TV show to help inspire me. Bounce ideas off friends, family, writer buddies, or co-workers. You may be the one writing the book, but it doesn’t mean you have to do it all alone.