When you open the plasmid sequence, you will notice two cut sites for BplI enzyme located just before a section labeled "gRNA scaffold". Then, you can use the BplI enzyme to digest the plasmid and insert your gRNA, which needs to be designed with sticky ends for ligation with the digested plasmid.
You can use SnapGene to download the map of the 84232 Addgene Plasmid. Open the DNA sequence file in the Snapgene software and look for gRNA scaffold. When you select typeIIS enzymes in the Enzyme tab you will see two sites for BplI enzyme upstream of the gRNA scaffold. When you design gRNA you should add the overhangs to your gRNA oligos. Anneal the oligos and clone into the vector.