You are talking about military retirement? This is entered in the same place a all 1099-Rs are entered.
Do a Search (upper right) for 1099-r and click on the Jump-to link (Mac users must find 1099-r in the Topics List). Just enter 1099-r and hit enter - ignore all the suggested search terms.
Be sure to check the following screens in case you are asked about the source of the 1099-R.
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