You can find the resource settings in the Class Defaults of the resource blueprint, you can find all the included resource blueprints in the Resource folder shown below.
Once you open one of the resource blueprints such as the BP_WoodResource you can find all the resource settings. The first settings are the Resources settings which control the items the player receives when the resource is harvested.
Here you can set multiple items and set the Rarity, the higher the Rarity value the more likely the player will receive that item when harvesting the resource. You can add new items to the Items array by selecting the + button and to remove an item click the down arrow button and select delete.
The Min Resource Count and Max Resource Count allows you to set random resource amounts for the resource blueprints. A random value between the Min Resource Count and Max Resource Count will be used as the total resource items the resource has and the player can collect before the resource is destroyed.
The Despawn settings allow you to control what the resource does when its resource amount is 0, the Resource Depleted Effect controls what the resource will do, Fall Over which is used by the wood resource will make the resource fall over like a tree being cut down. You can also select none which will make the resource be hidden once depleted.
You can also set the Resource Depleted Sound which will play when the resource has 0 resource amount. The Hide Resource Mesh Time is used when the Depleted Effect is set to Fall Over, this is the amount of time before the mesh is hidden after falling.
Respawn setting allow you to set if the resource will respawn and how long it takes before the resource respawns using the Respawn Time, this value is in seconds.