On these websites you will find additional help, such as definitions, grammar exercises and reliable translations.
Spanish Dictionary: www.rae.es
Bilingual Dictionary: www.wordreference.com
Translations of words/phrases: www.linguee.com
General Spanish grammar: https://studyspanish.com/grammar
Grammar exercises: https://personal.colby.edu/~bknelson/SLC/
Topics of Spanish grammar, vocabulary for different levels, conjugation and uses of verb tenses, spelling rules, etc.: https://www.tuescueladeespanol.es/recursos-gratuitos-para-aprender-espanol/