Can't access Inventory Slot

Hello guys, I really need your help, I need to cast to Inventory Slot from the Player Character or Controller, but when I try I always fail. I tried to do this>

and make it variable in the Inventory Window. When I try to get access to it by casting or this way>

I fail. Here is an image from the Inventory Slot>

. The whole system uses Component, here is an image that shows the part where the Inventory Window is used.>

Please help. I just want to Cast to Inventory Slot from Player Character or Controller. Thanks for the time you spend to read this and eventually help me :slight_smile:

Have you already looked at this tutorial?