Plan the first steps for a side project

Help me plan the first steps for a side project.

The idea: [e.g. start a podcast, write a book, sell my crafts, build an app]
Why I want to do it: [fun / learning / extra income]
Time I have each week: [e.g. 3 hours]
Skills I have and don't have: [list]
What success looks like in 3 months: [one line]

Ask me up to 3 questions first if anything important is missing. Wait for my answers.

Then:
1. A first-month plan, week by week, in steps of under an hour.
2. A cheap, quick way to test whether the idea works.
3. The first thing to do this week.
4. What to ignore for now.

UK English. Don't invent costs; leave blanks for me to fill in.

Stay in this ChatGPT chat. Do not turn on apps or connectors, and do not use memory from another chat.