You can start anywhere but the place is probably to have him step up. I am saying on a perch or you but w/ you my concern is him biting & riping you up or worse, going for your hand, wrist or fingers. If you can't control him in an emergency then he may get hurt or killed (like a fire). I know you don't want to push him past his comfort zone but... In these situations it's critical... Which is the 2nd thing I taught Buddy. The 1st was teaching him about allowing my hands into his nest cage.
After I taught him to step up & down, & turn around we worked on getting in & out of the travel cage for transport to the vet. Good thing too because he when got to the vet he had a salmonella infection in his mouth. He was acting off just a few days before the appointment, I didn't even know @ that time how fast a bird could die from something as simple as this type of infection. Now I know & if Buddy ever acted off he'd be into the vet alnost immediately.
I've never used a clicker w/ Buddy he works w/ me using verbal cues like Awesone, Excellant, Good boy! With the addition of sunflower seeds & other treat incentives. I know most hear use a clicker but I got Buddy 25 years in & I know my Dad gad used a training perch when he was young. I believe there was a clicker on the table but I'm not positive. Although Buddy barely says anything he has a fantastic understanding of the english language, I got lucky w/ him being an Amazon. Paco isn't thought to be as old but being a Grey, you may be surprised how well he understands. (I didn't really know how much Buddy understood till I trained him).
Find some really good Yummy's & have at it w/ Paco. Just try to be consistent w/ times to start. I do Buddy's stuff after dinner before bed. There's a few hour span in there. After you 2 understand training time = him working then you can do it when ever but to start try to make it as close to a scheduled thing as you can. Keep in mind if he's very food motivated you may have to do it before a meal then later add in the verbal praise w/ less treats.
Well believe it or not, I have gotten him to step up onto my arm with out any biting. I backed off for a while and I only attempt this in the eveing, no stress from me, I don't have to go anywhere, so I just take my time. When I do have to work, I keep the same routine, eat, feed him, shower and I talk to him the entire time, "I have to go to work, time to go bye bye, etc" I bribe him with a treat in his bowl. In addtion to improving our relationship, I want him to spend more time away from the cage as well. I hope to work up to getting him on the T stand but that's a ways away. He is still scared, I just hate to think his world consists of the corner of a bedroom on top of his cage. Another reason to start advancing trust and improving his world.
I think a clicker might scare him. He has learned to know that a treat is special something other then his morning and evening "goodies, Yum yum" LOL lordy I sound silly.
I do worry what if I had an emergency or had to get him into a smaller cage in order to get him to a vet. It would be quite a challenge and would put us back in trust by miles.
Thanks everyone for your tips. With 30 days stuck at home it's a perfect time to work on this.
Oh and I too had a Wild Caught White Front Amazon. Even though she never uttered a word other then hello one time we could communicate really well. She even learned to fly to her cage on her own when I was leaving. At first I thought she saw me put on my coat, but I later figured out that she heard my keys jangle. Parrots are amazing no matter what the breed.