Ordering components to build drawing

I would like to build out the device in the drawing below.
Can someone help me select the components needed?
I tried inserting a link and also tried uploading a picture. Not sure if they will work.


Are you looking for through hole or surface mount components for your build?
What are the voltages for the capacitors that are not listed?
What wattage for the resistors?
What are the diodes for the red, green, and black in your circit?

Components can be whatever is easiest to build. I plan to put the whole assembly in a cabinet, so appearance does not matter.
What I want out of this is a device that alternates on and off for an adjustable time period… say, on for 3 minutes, then off for 3 minutes.
I can use the on and off in combination with a RIB to use the NO and NC options connected to a pair of Aube RC840 relays to alternately run two heaters.
Ideally the whole thing would be run off 24V.
The diodes are just a “bell and whistle” to know which circuit is currently active. They are no mandatory.
Supposedly the resister are what determine how long the delay between switching is.
If there is an easier way to do this, I am all for it.