Online calculator and the amperage you expect with the duty cycle you expect at the frequency you expect. I have my own private rules of thumb that I use for my layouts, but for what you are doing? Start with double the minimum of the board house you are using. Maybe 25mil trace and 25 spacing for the logic? If that’s too big, start reducing the spacing before you reduce the trace width. For the Power, 100mil/100mil is plenty.
Sorry, short hand, you might run into it when you are looking at the manufacturing capabilities of the PCB houses you want to order from. 6/6 Means 6 mil (english units not mm!) trace width minimum / 6 mil spacing minimum between traces.