If anyone knows of a tutorial on how to add objects in a game through script please insight me. Ex: Player picks up a wooden shield barricade and puts in in their hands, have it show a placement cursor and allow them to place the shield anywhere they want according to placement requirements. Thanks in advance!
Look at: Instantiate (for prefab) or just transform.pos + Raycast for your example of pick up, put down; also search for hundreds of similar questions, tuts, vids, code snippets etc.
Provide the user a small GUI tool to tweak pos/rot of x,y,z if you want to get fancy