that scroll is not tied to the battle summons, its only for the cosmetic ones. there is a different item for battle summons

He is right. Summons that you c*e as pets have the blue text "new summon function" above it. These do nothing but follow you around.

Then there are battle summons that activate upon using your main's mystery. These currently have a "coming soon" text over it.

The summon on the left is your battle summon, the one on the right is your chase summon.

You can obtain battle summons by upgrading the hexagons and upgrading with purple essence. These cost about 560 group points in CN atm.

Source: I play in CN