Hi. You can call all hands listed, regardless of position. The hands you should raise, have also to be listed in the "First In" chart for you to raise them (according to your position).
For example, if there are already 3 callers in front of you, you can call any pocket pair (22 - TT), and position doesn't matter.
But if you're holding A8 offsuit in MP1, and one of the UTG players limps, you have to fold your hand, because according to the "First In" chart you need at least AJo to raise from this position. This is because there are still 6 players left to act behind you, and one of them could have you dominated (with a better ace), and you would have to play your hand out of position.
But if you are in the CO, you'll raise the limper with A8o, because with only 3 people left to act, it's unlikely someone holds a better hand than yours, and you are probably holding a much better hand than the UTG limper, so you want to isolate him, and will also have the advantage to play in position.
You should mostly check the "First In" chart when you're about to isolate 1 limper. If there are more limpers, almost all hands you should raise with, will be listed in the "First In" chart (only exception being ATo against two or three UTG limpers).
