As you dive into the game, there are two terms that will become very important to you, Action Points (AP) and Exotic Matter (XM).

AP is earned through performing actions and is pretty much the same as Experience (XP) earned in many other games. AP is cumulative and when you earn AP, it should flash at the top of your Ingress Scanner. As you earn AP, you will pass milestones which will designate you with a higher level. A higher level is needed to use higher level items, e.g. you need to have a Access Level of 2 in order to use a L2 Resonator.

XM is collected as you travel. While looking at your scanner you will see little blue particle looking balls. As you travel towards them and they enter within range (blue circle), you will collect them to your reserves. XM is important, because it costs XM to perform actions, e.g. it costs a certain amount of XM to hack a portal.

 

This table lists all the possible actions you can perform and what base AP amount you earn for successfully performing the action.
Action Action Points
Hack a portal (Enemy) 100 AP
Hack a portal (Neutral or Own Faction) 0 AP
Recharge a Portal 10 AP
Place a resonator (new resonator) 125 AP
Upgrade your resonator 0 AP
Upgrade another's resonator 65 AP
Capturing a portal (place the first resonator) 500 AP
Complete a portal (place the eighth resonator) 250 AP
Link two portals 313 AP
Establish a control field 1250 AP
Apply a portal shield 0 AP
Destroy a resonator 75 AP
Destroy a link 187 AP
Destroy a control field 750 AP

 

This table lists the possible Access Levels and your capabilities at that level.
Level AP Threshold XM Capacity
1 0 3000
2 10,000 4,000
3 30,000 5,000
4 70,000 6,000
5 150,000 7,000
6 300,000 8,000
7 600,000 9,000
8 1,200,000 10,000