Gearing for dummies

[ourclarioncall]

Trying to understand gearing . https://youtu.be/10FUOq8TKTk  The guy in this YouTube video says he started with 40 x 17

Then went lower to 38 x 17

Then lower again to 34 x 17

So that makes sense to my brain . The lower number teeth on the chainring the lower the gearing , the easier for climbing hills/mountains loaded up. He has gone down from 40 to 34. Perfect , makes sense
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But then in Thorn literature the gearing is recommended at

Newbie whose not sure start 48 x 17

If you want to go low 40 x 17

Even lower 40 x 19

So.... to get the “even lower” the sprocket went UP from 17 to 19 ??

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So here the assumptions I’ve drawn , feel free to blow them out of the water .to get LOWER GEARING you can either drop the chainring teeth number down or raise the sprocket teeth number up?

True or false?

I should really sit down and study this stuff but getting time and silence (I really need quiet to concentrate) is very difficult in hectic family life.

[PH]

So here the assumptions I’ve drawn , feel free to blow them out of the water .to get LOWER GEARING you can either drop the chainring teeth number down or raise the sprocket teeth number up?

True or false?

True, if you leave the other the same that's exactly what happens.
The numbers don't really matter it's the relationship or ratio between them.  How many times the sprocket goes round for everythime the chainring does.  So  30/15 would be the same as 40/20, every time the chainring went round the sprocket would go round twice.

I should really sit down and study this stuff but getting time and silence (I really need quiet to concentrate) is very difficult in hectic family life.

You don't really need to, it won't improve the cycling at all, it can be quite interesting if like some of us you really have nothing better to do, but even for us it isn't a priority.  Just start with the recommendation, see how you get on and adjust from there.