Simple backpack extra storage help

[xXx_burton_xXx]

Hi, can anyone help me out with making an item that when gets clicked, it opens up a new inventory pg for room for more items to fit in it. Pretty much just like the one on resident evil, a simple click and new pg inventory slot appears. and the backpack isen't an ability its purely just an item you pick up that gives you more space.

 

[xXx_burton_xXx]

k well tigger...not an item sorry 4 the mix up, but a trigger that makes and item able to store more items