You need to join a clan if you want to find teams for Prison of Elders; it makes a lot easier. I find games by posting on the wall for the Xbox One & Xbox One Raider clans, and there's also some handy threads in the Recruitment forum which are dedicated to finding teams for specific activities on specific platforms. Add those to your Favorites so you find them easy whenever you need a team. That said, Bungie does need to add more ways of earning Etheric Light... especially for those who prefer to play solo. Maybe make it so that the first Daily Heroic of the week gives you a piece of Etheric Light? Kind of like how you're guaranteed 1 free Treasure Key a week for your first Queen's Wrath bounty on any character.