"Get an idea on/of something"

In general, is it better to say get an idea on or get an idea of something?

Here are some examples:

In order to get an idea on how to build this house...

In order to get an idea of how to build this house...

In my opinion, the first example sounds better. Which one is grammatically correct?

In English, one has an idea of... (as well as other prepositions)

In order to get an idea of how to build this house, I spoke to several architects.

We may think on a matter.

The more I thought on the matter, the more convinced I became that I had been wrong all along.

Personally, I would say that I get ideas about things, not on or of things.

Example:

I had a good idea about how to answer this question, but I wrote this instead.

...get an idea on how to build...

...get an idea of building...

Use of before a verb + -ing.