Conditionals:
Explanation in English
https://www.englisch-hilfen.de/en/grammar_list/if.htm
http://www.grammar.cl/english/conditionals.htm (Chart)
In Spanish
https://whatsup.es/blog/aprende-por-fin-usar-condicionales-en-ingles
Practise with the form
https://www.englisch-hilfen.de/en/exercises/if_clauses/conditions.htm
https://whatsup.es/blog/aprende-por-fin-usar-condicionales-en-ingles
https://whatsup.es/blog/aprende-por-fin-usar-condicionales-en-ingles
Practise with the use
https://inglesaway.wordpress.com/2013/05/08/grammar-zero-and-first-conditional-sentences/
http://wwwedu.ge.ch/cptic/prospective/projets/anglais/exercises/condit2.htm
https://www.perfect-english-grammar.com/first-second-third-conditionals-exercise.html
For the brave
http://autoenglish.org/gr.conmixed.pdf