Strawberries are self-fertile. Strawberry plants will pollinate themselves, but they usually need the assistance of wind or pollinators, such as bees, to do the work of transferring the pollen from the stamens, the male parts of the flowers, to the stigma, the female part of the flower. Once you can identify the stamen you'll be on your way to learning how to pollinate your strawberry plants.
This year has seen a dramatic decrease in honeybees visiting my ornamental garden, which is causing me to worry about the vegetables and herbs I'm growing that rely on pollinators like bees on the balcony garden. My strawberry plants began to bloom in the container garden and the lack of bees has meant that I've had a lot of strawberry blooms to go waste. They've opened and withered without setting fruit, until I stepped in and act as the pollinator.