If your citrus trees are only small we would recommend that your remove any small fruits for the first two years, as heart breaking as this may seem it will give your tree the time it needs to establish into a strong healthy plant before you let it concentrate its precious energy on fruit production.
Citrus trees are highly productive trees and you can see from the number of flowers that your tree will produce more flowers and often set more fruit that it can hold to maturity. Citrus will naturally abort excess fruit but you may also choose to thin your fruits as this will give you less fruit but they will be larger in size.
Fertilise your tree once it has finished flowering and the tree has set small fruits. Use a balanced NPK fertiliser with trace elements. Don't make the mistake of using a high nitrogen fertiliser while your tree is flowering or you will get a mass of beautiful new leaf growth but no fruit.
Enjoy your spring blossoms and happy citrus growing.