Newbie making a Japanese meal for the first time, but not sure if I have everything?

So basically I want to make a rice and tuna bowl.

I have short grain Japanese white race, and canned tuna. I will be chopping onions and garlic, then using some cooking oil and Japanese soy sauce, and mixing it all in. I have no idea how it’s gonna turn out. Any advice or suggestions regarding this meal would be appreciated. I don’t want to mess it up. Would you say I have everything good to go or should I add more to it?

bon appetit