Once you have domesticated and uploaded to the GB database the sequences that you want to target with the CRISPR-Cas technology, you can assemble your guide RNAs with the CRISPR Assembler.
Select in the figure below the type of sgRNA unit that you want to build. The upper choice is designed for monocots and incorporates the Pol III U3 promoter from rice. Click the lower assembly when you intent to build a sgRNA for dicots using a U6 Arabidopsis promoter. Note that the PROMOTER-TARGET boundaries are different for each assembly type. Be careful to select the correct TARGET type according to your purposes when you domesticate your TARGET sequence with the GB CRISRP domesticator.