On the ruling planet's day and hour is ideal. You can use apps to find out the planetary hours.However, if you're not able to do all of that it's totally fine.
It's an app ..https://play.google.com/store/apps/details?id=com.technologies.mobile.astroclockThere are many apps that allow you to track planetary hours
All the conjuring hours are in the book it also states if you can’t do it on that day what u can do love
On the ruling planet's day and hour is ideal. You can use apps to find out the planetary hours. However, if you're not able to do all of that it's totally fine.