how would I get this command to work?

item replace block ~ ~ ~ container.0 with clock[custom_model_data=76396,max_stack_size=8,item_name="Rocket Step",custom_data={aeternum-ability:0,aeternum-ability_data:{ability_name:"rocket-step",type:"Activated",req_level:4,req_class:"mage",incompatible:[]}, aeternum-item_data:{no-access:0}}] 1 I know the issue lies in item_name but I can't figure out what the actual issue is