I have made boards like that many years ago. 1970s
Single sided and double-sided cost the same now. I would put the "jumpers" on the top side copper.
I did this in Paint.net just to make a point. The green is topside and replaces a jumper.
In any CAD there is an "area fill" command. The +12B is much of the rest of the board. The CAD can fill all unused areas with "+12B". It will look close to right.
View attachment 150156
One option: is to do what I did but in CAD. You will need to place all the holes and get the sizes right. Then connect up the traces. This option has many places to make errors.
Two option: Is to do it right. Start out with the schematic. Choose the right part for each part. Then start the PCB. Place each part about where it should be and start connecting the pins. At the end do area fills for the big area(s).
I probably would move the "+12B" to the top side "green" and let it fill the much of the board. Usually "GND" is most of the board. Or they share the topside.
Run the traces on the bottom side.
Before you put time into this check to see if you can get the parts. You can get 1/4 watt resistors OK but the caps are of concern. I think you might need to pick parts that you can get.