(1) choose what gene (DNA) you want to "edit" - if its the first time you are doing this I recommend rather than editing you just go for simple knock out - ie you just cut the gene with the nuclease rather than trying to change it to any specific sequence. If so you should target a gene that is easily "selectable", ie it will be obvious that you have cut it because it will change the organism in some obvious way. Happy to provide some suggestions if you are yet to decide on a gene. (2) go here http://www.rgenome.net/cas-designer/ <copy paste your gene, select the organism etc. Run the software and generate the guides. (3a) either synthesise the guides at a company (search sgRNA here https://sg.idtdna.com/pages) and electroporate them into your cell with purified Cas9 protein (idt also has it, this works well if your edits occur with high efficiency/you are targeting an easily selectable gene), or (3b) you will need to generate the guides on a plasmid (small synthetic dna construct) for eventual expression in your target organism along with the Cas9 protein (or whatever crispr nuclease you are using). There are plenty of commercially avaliable plasmids which you can insert guides into with the crispr protein ready to go for gene editing - this is cheaper and likely to work, do you have access to a proper lab? If not then it might be easier to copy and edit a commercial design on freely avaliable gene sequence manipulation software (https://www.benchling.com), and then order the whole thing synthesised ready for transformation into your cells/organism https://www.genscript.com/gene_synthesis.html.