An Idaho Medical Savings Account is not the same as an federal Health Savings Account (HSA) - it is a separate account altogether.
As the state says: "Contributions to a federal MSA or health savings account (HSA) don't qualify for this Idaho deduction. The following information refers only to the Idaho MSA; tax consequences of federal MSAs and HSAs differ from the Idaho MSA." See https://tax.idaho.gov/i-1162.cfm
So, do not enter your HSA contributions on this Idaho screen ("Idaho Medical Savings Account (MSA)").