How often do I have to be monitored by any of these medications Prednisone, methotrexate, folic acid?

The timing depend. On how long you have been on methotrexate. The timing could be 2 to 12 weeks apart depend new start vs maintainence and whether if you had side effect in past. Should discuss this with your rheumatologist. .
Depends. It depends on what you were prescribed these medications for, how long have you been on these and how did you react in the past. This matter is best discussed with the prescribing doctor. Also make sure that your doctor wants you to take both methotraxate and folic acid .