check online for grooming schools in your area. and then go to sites like Ripoffs.com and see if you find alot of negative about them also find some groomers in your area and chat with them I know some of the groomers here in AZ shared negative and positive info they had about different grooming schools with Me I was considering going so I could groom Marlo myself but then got busy with my daughters school so changed my mind still may go at some point but right now the School keeps me busy
I wouldn't pay for grooming schools as there are a shit ton of them around, and probably alot of them would be glad to train you if you were to volunteer there and not get paid. My ex used to train a few girls that came into her shop to volunteer over the years to get experience but only one of them that I know of actually opened her own shop and became very successful good luck in your endeavor.