Getting to the first bonfire

After the introduction ends
Take the first junction to the right for Soul of a Deserted Corpse.
After coming to an open area, loot the body near the fountain for Ashen Estus Flask.
Take the right path for a Soul of n Unknown traveler and a battle with a giant Crystal Lizard.
Defeating the giant Crystal Lizard will give you a Titanite Scale.
Make your way back to the open area and go straight for Cemetry of Ash bonfire.
Light the bonfire to learn the gesture Rest.

Getting to Iudex Gundyr

Go all the way down the cliffside for 5 Firebomb.
Going straight from the bonfire, there will be a message teaching you how to jump. Jump from the edge of the cliff onto a small ravine for a Titanite Shard.
Remove the Sword for a boss fight against Iudex Gundyr.
Defeat him for a Coiled Sword.

Boss fight Strategy in Dark Souls 3

VS Giant Crystal Lizard

You can use a shield to guard all it’s attacks. Your best chance of attacking it is right after it’s attack motion, so be sure to guard or dodge them. Once it does a breath attack, crystals will appear beneath him causing you damage if hit by it.

VS Iudex Gundyr

Remove the sword stabbed through the statue in the middle for the courtyard to activate the boss battle. He will use a halberd type weapon and each attack has a wide hit radius. If you have a shield use it. If you are willing to dodge his attacks it is best to roll counter clockwise.
After his health gets to 50%, he will transform and grow a black creature. You can get some hits on him when he is transforming. He will sometimes jump up high in the air to attack you so be sure to dodge his attacks.