If by 'big grammar' you are referring to important grammatical concepts, you could say: 'Esto es un concepto gramatical importante.'
perdonen mi gramática
grande is big in Spanish. pronounciation (grondeh)
Importante. Eem-por-TAN-tay
grande
grande
Grande.
You say, escuela primaria, or just primaria. They'll know you're talking about a school.
The big party would be "El fiesta grande" in Spanish.
Gran familia is the best way to say "big family" in Spanish.
englesh to spanish
This means "Our team always wins when we share". It seems to be proper grammar.
It's not a big deal to say me, Ericka, and Ethan. However, you should probably say: Ericka, Ethan, and I.