Bit of Grammar

[Bullet_Bang]

Sir,

Can we use a sentence like the following? Note: This person is planning to travel around the world..

Furthermore, if I spent a year travelling, I would learn more about the world.

That " spent " came there just because of the usage of "would"?

Another confusion,

"But I believe that it would be easy to make a bit while I was travelling, giving English lessons or working in hotels and shops."
1. Don't we have to put a comma after that "But"
2. That bold "would" causes the "was" ,right? Is that a common practice? Is it a must to use past tense if we use a would?
3.Shouldn't there be a "by" before "giving English lessons or working in hotels and shops"?

[Jamie (K)]

You need to look up the "conditional mood" in an English grammar resource. This is not the past tense you're dealing with here, but the conditional.

[Bullet_Bang]

Thank you so much!