Questions about UX design process

Hello! I’ve got a question. After you’ve done your research, how do you begin your sketching process? Do you do flowcharts/ wireflows or sitemaps first?

Can a website or app have just one user flow? Do you design user flows before or after you’ve created your mockup?

Thanks

paper & pen OR ipad & apple pencil

I like the concept of ‘red routes’. While there are probably a lot of user stories to cater to, it is best to select one, or a few, premiered flows. These are the ones I start with, and deal with lesser routes once the overall journey is defined.