If you join Ryanair as a direct entry rated FO it will take around 18 months before you could commence Command Upgrade training. You would be required to attain the required grades in your initial OCC sim training and then two recurrent sims. Accompanying this you would have three line checks (3 months apart) before you would go on the annual line check system. You would also have to complete one full winter season. After each simulator and line check the trainer would fill in a command upgrade assessment that is attached to your file. After all those boxes are ticked you will do coaching and assessment flights from the RHS and upon successful completion you will do a command interview with the training department. Once all of that is complete you would be eligible to commence a course when there is a requirement.
As I said plan for 18 months minimum.