I thought about a cool game concept - it's a multiplayer game app, and everyone playing it can have one action per day.
the game will be mostly about strategizing the best action and creating allies and enemies in the process.
can you expand upon this idea for me?
There are a few different ways that you can expand the concept which you've outlined here.

1 - What is the setting of your game?  Does it take place on a certain planet, or during a certain timeframe?
2 - What are the mechanics of the game?  What actions can players take?
3 - How is an enemy or an ally determined?
4 - How do players progress in the game?  How do they win? 
5 - What events take place in the game independent of player actions that help guide the gameplay?

By incorporating these kinds of elements to your initial outline, you'll eventually reach the point of being able to put code in place to accomplish your goal.
Can you answer these questions for me? I have my own answers but I want to see some other ways of interpreting the idea
Sure! here are potential answers:

1 - What is the setting of your game?  Does it take place on a certain planet, or during a certain timeframe?
The game is set in a universe with multiple inter-galactic civilizations. the player will play one of those.

2 - What are the mechanics of the game?  What actions can players take?
The mechanics are resource gathering, battles, crafting and trade.
Some example actions could be:
a. Gather a resource
b. Buy crafting resources
c. Craft a battle ship
d. send battle ship to attack another player

3 - How is an enemy or an ally determined?
An enemy or ally is determined by what the player thinks.

4 - How do players progress in the game?  How do they win? 
Players progress in the game by building larger armies and creating a automatons that reduce the need to spend their daily commands on basic tasks. There is no specific win condition however there is a leaderboard with various categories

5 - What events take place in the game independent of player actions that help guide the gameplay?
There could be multiple events, one such event could be a worm-hole event that allows players to send more than one command every day.