How to use "......的话“

的话 is a particle, it is used after the first clause of a hypothetical complex sentence to introduce the following contents.

For example:

1.（如果/假如/要是）有时间的话，我就去。（I'll go if I have time.）

2. 有时间的话，我就去。（I'll go if I have time.）

如果/假如/要是……的话，就…… = ………的话，就……

For example:

1. 要是我有很多钱的话，我就去世界旅行。 = 我有很多钱的话，我就去世界旅行。

If I had a lot of money, I would travel around the world

2. 如果我有时间的话，我就去。= 有时间的话，我就去。

I'll go if I have time.

3. 假如我是你，我就跟他分手。= 我是你的话，我就跟他分手。

If I were you, I'd break up with him.

Notes:

The conjunctions 如果, 假如, and 要是 all indicate supposition and are all used in the first clause. The correlative adverb 就 is used in the second clause to indicate the result produced from the supposition.

The 的话 can also be used alone in the first clause, omitting the 就 in the second

For example:

1. 我不去的话，你还想去吗？(Do you still want to go if I don't?)

2. 有时间的话，我会陪你去逛街的。(If I have time, I will go shopping with you.)

假设

In the case of

天气好的话，我们就出去。=如果天气好，我们就出去。

假设时用，similar as “if” in English. 
If it rains, I won't go. 下雨的话，我就不去。

表假设的时候用，if语句。

I am learning this too. 的话 is usually attached to the first clause of a conditional statement. 

如果我想吃的话，就去买一袋饺子。

If you want to eat, buy a bag of dumplings. 

…的话 is used to assume a case , it's a  hypothetical situation. normally followed by a sentence  stating -- under this situation what the subject will do. 

在你想说"如果"的时候

如果…hypothetial situation/condition…(的话)，S.+就+result

如果…hypothetial situation/condition…的话，S.+就+result

(如果) hypothetial situation/condition…的话，S.+就+result

如果有问题，你就给我打电话

如果有问题的话，你就给我打电话

有问题的话，你就给我打电话