What do you do to evolve onix Pokemon indigo?

these are by steps:

step 1:go to pokeshop

step 2:buy metal coat

step 3:go to my zone

step 4:click the link (setup my battle team/view all my Pokemon)

step 5:click on onix

step 6:click attach item

step 7:click metal coat

the page will load

step 8:again click onix

the evolution will come (evolve onix into steelix)

step 9:click the evolution and onix will automatically change into steelix