The Alliance System earns you and your friends 
Coin by recording your gained XP or experience per week. Even after hitting level 30, you still gain the usual amount of XP, but these XP don't contribute to anything anymore besides your Alliance Tier. A Maximum of 144,290 Coin can be earned by doing all daily, weekly and alliance activities over a period of 28 real days.
Anytime you complete these expedition types: Contract, Freeplay, Stronghold, Competitive Strongholds, Echoes of Reality (Game Mode), you earn experience. That experience will be counting towards increasing your Alliance Tier. You also gain a share of the experience of your squad members (random or friend doesn't matter here) per expedition, except in the case of Freeplay. The net XP gained is the sum of your XP and the sum of 25% of each of your team mates' XPs after truncating all values after the decimal point.
Net XP Gained = <[Your XP] + [(Teammate #1's XP)/4] + [(Teammate #2's XP)/4] + [(Teammate #3's XP)/4]>
The top five Contributors to your "Alliance" are then taken into account at the end of the week. The game automatically chooses the top five and you can check on your current standings and the selected friends in the enclave. If there are only 4 or fewer people in your friend list or Guild, your own alliance contribution will be considered. However, only a maximum of 4 Alliance tiers worth of rewards can be earned with your own Alliance contribution (i.e. it caps at 755 coin only).
Note:Your alliance will be taken into account only if you play with other players (in private mode with at least one friend or in public with any random teammate). Otherwise, your alliance contribution will remain at zero. Also see Privacy Settings.
Friends contribute 5x the Coin compared to the top random player, which results in friends almost always taking priority for the top five slots over the top random one, unless your friends are very inactive. Guild members' contributions are automatically considered and prioritized over friends.
Guild members will guaranteed contribute a small amount of additional coin when reaching the max tier (beyond the Tier 10) circle. This can give an additional coin gain of 1200 coin (in total). While only guild members can do this and members from your friend-list only cannot do this, sometimes this gets neglected (likely due to a bug) and members from friend-list will also be able to achieve this, but without a guarantee.
Regardless of how many people have contributed to your alliance (including yourself), an additional individual contribution is added to your coin gain. This could be considered as the payment for your Freelancer duties you have performed, like a salary or hazard pay of some sort. Note that this is additional coin and not alliance coin gain.
Important: Contributions are not made retroactively, they only count from the moment you add them to your friend list (or played with the random player who ended up as your top random contributor). This is why it is emphasized, that friends need to be on your list or a guild must be joined, when the weeks starts, not added on later.
Pictorial Depiction of the Alliance Bonus
Click on the below image to fully see it in 600dpi.
