The Drip Acclimatization Method
The idea of this method is slow equalization of store/shipping bag water with your tank water.
First of all, dim light in your room and slowly and carefully open a package with shrimps. Bright light after a long dark period can stress shrimps.
Carefully pour water with shrimps into 0.5-2 empty liter container.
Place a box near your tank and set up a siphon drip line from a tank.
As a drip tube I use ordinary air tube with an air stone on aquarium side and a check valve on the container side. Air stone prevents tank shrimps from travelling into the container and slows down the current. Check valve slows down the current as well. You can use a control valve instead of it or just make a knot on a tube. This all methods are good as long as they slow down the current.
After your tube with other ‘accessories’ is set up, you might need to suck a water from a tube to make it drips and then adjust the current.
Adjusting the current can be done by controlling your control valve, making a knot tighter or just moving a container up and down in comparison with a tank water level. Look at the picture of one of my set ups.
Let water double or triple bag water amount and remove a half of the water. You can increase a dip current now. Repeat this several times.
This whole procedure can take 1-3 hours, depending on your set up and preferences. At the end, almost all water in the container will be tank water.
Finally carefully caught shrimps by a net and put them into the tank. Do not just pour water from container directly into your tank. If your shipment has some plants and you wish to keep them, wash plants them before using in a tap water.
Described approach is good for shrimps that do not require warm water. Some shrimps like Sulawesi shrimps need to be kept in a heated tank.
However if your aquarium water is hotter than your room, you should equalize the temperature. I usually keep container with shrimps in a bucket with warmer water. Water outside the container should not be hotter than your tank water. Overheating can cause more trouble to shrimps than cooler temperature.