Did you like this gGrammar sSnack? What did you do yesterday?

I hadn't heard of Grammar Snack before, but it looks like the title of a video or article series, which means you need to capitalize each word.

Grammar snack is a good ideaway to learn English.

Alternatively, "Using Grammar Snack to learn English is a good idea."

wWhen I read a question, I think aboutof my answers before I read the answer of gGrammar sSnack answer.

Thatis makes me remember one thing longs better.

It's unclear what "one thing" is referring to.

Yesterday, I learnt some new words, by listening to, reading and writing of English on YoutTube.

If you are using American English, swap learnt for learned.

I learn English by myself.

I am exciting about the program offered by Cambridge.

Your sentences will be better if they are connected. Also, what program? Presumably an English-learning program, but the reader won't know that unless you tell them.

I begian from Starters.

This program is for a children.

Because I realized that a child can learn a new thing better than a adult.

You can connect this with your previous sentence with "because."

They learn with their hearts, in their happiness and relaxingation.