I assume you've created the equivalent of a 256 bit number by throwing dice.
First, you need to ensure your number is less than 2252+27742317777372353535851937790883648493 (which is the group size of the base point G).
This gives you your private spend key.
Then you need to compute a keccak(256) hash of the spend key, interpret the resulting 32 bytes as a number, and determine that number mod 2252+27742317777372353535851937790883648493.
This gives you your private view key.
If you want to generate your seed from your private spend key, you need to convert it to base 1626.