(1) Translating BLAST allows you to convert a nucleotide sequence into protein sequence or vice versa, and then compare with the NCBI database.  We are going to introduce one of the Translating BLAST, Nucleotide query - Protein db [blastx].  Translated query - Protein db [blastx] converts a nucleotide query sequence into protein sequences in all 6 reading frames. The translated protein products are then compared against the NCBI protein databases.
 

(2) First go to the homepage of BLAST.  Then Search for Translating BLAST and click the Nucleotide query - Protein db [blastx].

(3) You can paste the nucleotide sequence in the space of search, in the choose a translation section, choose blastx.  Then u can choose database, such as rat, drosophila (normally we use nr, non-redundant for human genome).  Then click blast!.  Then click Format! to start the search.

(4) Then a new browser which will automatically update will be opened.  Wait for a while until the search finishes, and the result will be displayed in the new browser.

(5) When the result is displayed, see the picture of distribution carefully.  Click on the bar which makes the greatest alignment, this protein sequence is most probably the translated protein of the query DNA sequence.  In the alignment section, You can see how much the translated protein of your query sequence similar to the that in the database.  You can click on the hyperlink for more details of the protein.