If you know electronics it’s just to learn how to use a cad program. I would go for eagle since it’s free, easy to use and has a lot of documentation.
Once you know how to use the program, then it’s time to learn how to make the design reliable.
Anybody can draw a few lines between resistors and caps and make a PCB but not everyone can design a reliable circuit with lite interference. You can read books/ appnotes about PCB layout but if you understand the circuit and the physics behind it, then you should be set.
Draw the circuit in Eagle and make a PCB, read appnotes and layout guides. Make some power supply circuit, RF circuits with µC's and read the datasheet of the components used. Most questions can be answered by reading through the datasheet a few time, they even have example/ recommended circuits in them (I’m looking at you Linear

) It takes time but if you practice then you can become a pro in no time!
Use JLCPCB.com for cheap PCB’s, it will be a life saver!