You have to go to Grand lift of Dectus.

And verify you have both Dectus Medallions.

You are now on the top side of Dectus lift.

Mark top of staircase outside Leyndell.

And then go to the marked location (top of staircase).

You have to zig zag to top to avoid the attacks.

Defeat enemies and activate inside grace.

The grace is called Perfumer's Grotto.

You have to go outside to allow fast traveling.

Fast travel close to the four Belfries.

You will need to get Imbued Sword key from top Belfry.

Activate nearby the four Belfries grace.

And mark first belfry and go there.

After that, you have to use Imbed Sword Key on statue.

Then teleport to Crumbling Farum Azula.

It is only a small part of endgame area.

The goal is down to that endgame area.

You have to fast travel to Perfumer's grotto.

Hold the Playstation button for 1 second.

And hover selection on Elden ring game.

Press options button, select close game.

Run game & press X3 times to continue.

You are now in the endgame area!

You have to follow path to nearest grace.

And activate Crumbling beast grave grace.

Activate Crumbling beast grave depths grace.

And fast travel near brother Corhyn.

You will need to go and speak to brother Corhyn.

Give the ancient dragon prayerbook.

Back up O and select Study Incartations.

Buy Ancient Dragon's Lightning Spear.

And buy Ancient Dragon's Lightning Strike.

And put both spells into memory slots.

Rest of slots can be any spell.

Equip any sacred seal in the left hand.

And press up to select 1st dragon incantation.

Press left until the sacred seal in left hand.

After that, press L1 to use the selected Incantation.

Try Ancient Dragon's Lightning Spear.

Press up to select 2nd dragon incantation.

Try Ancient Dragon's lightning strike.

Refill FP (square) on cerulean tear flask.