Install the plugin by downloading the gplugin file and dragging it in to Geneious or use the plugin manager in Geneious (under Tools - Plugins in the menu).
Once installed, run the plugin by selecting a nucleotide sequence and choosing Annotate & Predict - Find CRISPR loci from the menu. Results are saved as annotations on your sequence.
Bland C, Ramsey TL, Sabree F, Lowe M, Brown K, Kyrpides NC, Hugenholtz P: CRISPR Recognition Tool (CRT): a tool for automatic detection of clustered regularly interspaced palindromic repeats. BMC Bioinformatics. 2007 Jun 18;8(1):209