It's quite simple. So before diving into the process let's talk a little about tissue culture and its benefits.
Plants unlike animals have the ability to grow all different parts of the plant from almost any part of the plant. For example in humans, the liver can regenerate by itself, but we cannot take a mass of liver cells and multiply it to form a new human being. With plants however, an entire new plant can be generated from any part of the plant. This is usually best achieved in a controlled laboratory environment to provide the optimal growth condition for the plant part to multiply, while minimizing the opportunity for competitive live forms(e.g. mold and fungus) to grow and overtake the growing plant.
This technique allows rapid cloning and multiplication of a plant and is known as Tissue Culture.
In the aquarium hobby, tissue culture has been widely adopted as a commercial production method of aquarium plants in addition to traditional method of farming plants and harvesting plants in the wild. There are several benefits.
Tissue culture plants are free from algae, pests and disease since they are grown in controlled laboratory environment. They are also quite affordable for the amount of plant that is grown and sold in a unit. But my favorite one is that it helps us enjoy the hobby without eradicating these beautiful plants from their natural habitats, which is usually a possible result, when there is huge demand and the plants are slow growers like Bucephalandras.
Ok, now let's get back to the subject.
In Tissue Culture, plants are grown in a gel medium which is a mixture of a medium (like agar), plant nutrients and plant growth hormones. They are prepared and grown in sealed containers to keep out pathogens and competitive life forms. When ready, they are sold in their growing containers.
So, when you buy a tissue culture plant, you will usually get a small plastic container that is sealed, containing plantlets growing in a gel medium.
If you are not ready to plant it yet, you can leave the container as is for a few days. Just give it some light for the plants to "cook" and make sure it is not too hot or cold.
When you are ready to plant, break the seal of the container and remove the contents.
Carefully remove all the gel medium from the plant. You can manually pull out as much possible or wash it off in a container of water or under a slow running tap.
Once all the gel medium is cleaned, separate the plantlets into individual portions in which you want to plant and plant them directly in the aquarium as you would with regular plants of the same species. That's really all that's to it!