Potted plants are sold as one or more plants in growing media such as rockwool in a plastic mesh pot. These can be left in the pots until you are ready to plant them. Just make sure that the media and plants are moist and you store them in a humid environment, that is not too cold or hot.
When you are ready the plant, remove the entire plant(s) and growing media from the pot. Carefully remove all the growing media from the roots. Tweezers can be used remove media stuck between hard to reach areas.
Rinse the roots to remove any loose media or debris. Then cut off any excess root. Don't worry, the plant will form healthy new root system after planting.
Remove dead leaves and shoots, if any, and divide the plant mass into individual plants or small groups based on how you want to plant them.
Plant the individual or grouped plants in your aquascape, provide them a healthy growing environment and enjoy!
TIP: When you are working with a large number of plants, make sure they stay moist until they are planted and the tank is filled. There are several options such as covering them with a wet paper towel or cloth, or misting them periodically with a spray bottle. A regular simple splash of water does it too!