How do i spawn items when being on the server? + how do i open a shop?

want to make a game using the open world template but i cannot spawn items and open the shop, tried to make a script so every second a new item spawns but nothing happens

how do i open a shop?

You can refer to this post below to make the shop:

Are you making a script that makes items? Can you show me the script?

To spawn they u can do that the item is automatically used, spawning the thing that u want etc. Example : Trigger : When a unit uses an item
If item type of last used item == ( YOUR ITEM )
then do:
Create projectile/the item u want to spawn with the item example create item at center of the entire map region etc.