Findin' out how much money you will need means makin' a list. On this list you put down what you will need to start the business and what you will need to run the business once it is started. Thinkin' about how much time it will take will help you keep from blowin' your mind once you start. While you are doin' that, someone is yellin' at you to do this. What you think will take an hour takes a day.
Little jobs turn into big jobs.
You never seem to have enough time to get anything done. The last hop in this dance step is skill. Folks usually are smart enough not to start a business if they don't know the technical part. Only a dummy would open a car repair garage without knowin' something about cars. Those same folks, however, might not think of the business skills they need.