I have two IRA's One I downloaded from Fidelity and it is listed on my 1040 Form on line15b. The other is from Thrift Savings Plan. I entered it using the 1099R provided. It is included on 16a/b, versus line15b. Is this correct? BTW, the IRA/SEP/SIMPLE box is not checked on the TSP 1099R.
Yes, that is correct, the TSP is not considered an IRA. It is set up in the manner of a 401(k) where contributions are taken from your paycheck.
Since it is not considered an IRA then not having the IRA/SEP/SIMPLE box checked is correct for the TSP.