However, setting up your Sentinels to actually earn meaningful rewards is a bit convoluted.
Once you know how to manage the mechanic though, it is surprisingly rewarding.
Set up your Sentinel Controller and maximize your loot with this walkthrough and strategy primer.

Here you will find a Sentinel Cache containing a Stalker Sentinel and the Sentinel Controller.
The button for this will reside on the left side of your inventory for the rest of the league.
However, youll need Sentinel Power before your Controller nodes actually do anything.

To gain Sentinel Power, all you have to do is use your Sentinels.
Finally,Pandemonium Sentinelsempower a large number of enemies all at once before disappearing immediately.
Apex and Pandemonium Sentinels are only available once you power their slots on the Sentinel Controller.

Each Sentinel has an empowerment stat that determines how much it powers up its targets.
Higher empowerment grants monsters increased life, damage, and damage reduction.
However, it also increases the quantity and rarity of items they drop.
All Sentinels have charges that determine how many times you’re free to use them.
Higher-level Sentinels typically have more charges.
Once you use up all of a Sentinels charges, it cannot be recharged.
Path Of Exile Sentinel strategies
Right now there are two main Sentinel strategies.
See the Controller layout above for an example.
This allows you to use your Pandemonium Sentinel twice per map and guarantees extra monsters when you do.
Activate your Pandemonium Sentinel near a large monster pack and watch the loot fly.
The other less popular strategy is to invest in Apex Sentinels to turn bosses into loot bombs.
That’s everything you’re gonna wanna gets tons of loot out of Sentinel!