A character, Pick up items and Blocks, materials and animation

Hello guys

this is my first post here, literally and i am not familiar with the request roles and system so please help me out

I’ve been working on a simple “mobile” game, followed some tutorials from youtube and started working my way through to develop it into a real game, at least for me as a newbie in this field.

anyways, i came close to finishing the game, but ofc as any game it needs some good designs and animation, and so,i have imagined the game theme, and the idea of the character, pick up items and so on.
I will need a character and its animations, and around 12 pick up / block items , materials for the map.

So , how is exactly the request process, can i ask someone to create some specific designs for my game, or do i post the idea, and if someone find it good he work on it and upload it to the market place or what exactly.

thanks for helping out ^^