By turning in-app 'Battery Saver' on, your phone's screen light automatically get dark while turning bottom up in your pocket. Pokemon Go continues operation, and its notification function is still available.
2. Select a starter
The first choice is not important in Pokemon Go, unlike other Pokemon games.
As sames as other Pokemon game series, you can pick 1 of 3 starters: Bulbasaur, Charmander, and Squirtle.
You can capture other two which you did not select. For example, even if you get Bulbasaur as a starter, you can capture wild Bulbasaur, Charmander, and Squirtle in Pokemon Go.
You can get Pikachu as a starter!
In Pokemon Go, you have another choice of starter: Pikachu. You can also capture a wild Pikachu.
Once your trainer level reaches 5, you can do gym battles and training (see 5. joining to team).
How to gain XP
Catching Pokemon to gain XP
By catching wild Pokemon, you can gain XP needed to increased trainer level. To raise level faster, you should capture Pokemon as much as possible. In Pokemon Go, you can see Pokemon around of you by looking footsteps.
To capture Pokemon, you have to throw Pokeballs at wild Pokemon. By throwing 'Curve ball' or throwing 'Excellently', you can gain bonus XP.
Spinning Pokestops By visiting Pokestops, you can gain 50XP and items like Pokeballs.
Hatching Pokemon Eggs You can gain XP and get Pokemonby hatching Pokemon eggs. To hatch an egg, you have to put it in an incubator and walk certain distance depending on egg: 2km egg, 5km egg, and 10 km egg.
Items like Super Portion and Great Ball are unlocked when you are at certain trainer level.
5. Joining to a team
Once your trainer level reaches 5, you can select one of three teams and join to it. The choice is completely up to you and does not influence story in Pokemon Go.
Gym battles & training
You can occupy gyms, have gym battles in gyms owned by rival teams, and do training in gyms owned by your team.
Wild Pokemon with higher CP You can see wild Pokemon with higher CP as your trainer level increases.
Raising max CP Your Pokemon can have higher max CP as your trainer level increases. That means Pokemon can be powered up more by raising trainer level.
Same kind of Pokemon may have different moves. Therefore, you may catch wild Pokemon a lot, and select the best one to power up based on what moves it has.
Additionally, Pokemon acquire different moves by evolving. Evolving before powering up to see what moves Pokemon learn by evolving recommended.
Here is an example: Moves of Dragonair and Dragonite
Dragonair's moves
Dragonite's moves
Pokemon with higher CP
CP is assigned to Pokemon, and the value of CP varies. To save Stardust and Candy and to grow Pokemon faster, you should select the one to power up based on its CP.
Transferring Pokemon to Professor Willow
You can get Candy needed to power up and evolve Pokemon by transferring Pokemon to Professor willow.
8. Gyms
Gym battles
Visiting rival gyms, you have gym battles. By winning it, prestige of the gym is lowered. Once prestige is at 0, you can own the gym.
Defending gyms
You can put Pokemon as defenders in gyms. You can get PokeCoin and Stardust by defending gym successfully. PokeCoin is what you usually have to pay for, and gym defense is the only resource to earn PokeCoin for free.