Starting Out:
To begin the Evolution path for Frost Demon, you must first reach level 850. Upon doing this, travel to the Other world and then proceed to fly behind the pikkon planet until the frieza planet (image for reference) is reached; the player can then talk to frieza who is wrapped in a cocoon who will prompt you to start the Evolution path questline. Click confirm to start the rest of the path.
Reference
Step 1: Angels of hell
The first quest given to you upon talking to Frieza after taking the path is to kill 20 Angels of Hell which spawn on the same planet in front of him in groups of 4. This quest acts as a regular quest as opposed to path quests.
Step 2: Player kills
After talking to Frieza once more he will give you a quest to kill 40 players with a level requirement of 100+ however a single player cannot be killed more than once within a 24 hour period to count towards the 40. This quest persists throughout all areas and upon rejoining the game, after each kill there will also be a counter appearing in the top right of the screen to show the player their current amount.
Step 3: Frieza Raid
Upon once again returning to Frieza and talking to him, the player will be teleported to a path raid on destroyed namek where a 10 minute timer is given in order to beat Frieza. The Frieza boss has access to both base form and golden form and will have a tendency to spam ki attacks. If the raid is failed a cooldown of 30 minutes has to occur before another attempt can be made. If successful the player will be rewarded with the Golden Form and their path questline is completed.