After having completed all exercises, you
will already be able to understand easy texts, with the help of the universal
dictionary.
When you are finished with
the exercises, and you care for more
explanation, you should consult Plena Manlibro
de Esperanta Gramatiko
of Bertilo Wennergren.
That grammar is written in Esperanto.
A more complete online
dictionary is available at Reta
Vortaro.