How to set Tab key to insert four(4) spaces?

Dear Everybody;
I am beginner to use Scrivener. I would like to set tab key which insert four(4) spaces during I write some text and/or codes.
It is highly appreciate that someone make advice to settle it.
Thanks in advance.

In general there is no such thing as 4 spaces as different fonts, sizes etc. would be different. However, under Tools/Options/Editor you get to set a default style. An example shows in the box with a quote and a ruler on top. If you right click on the ruler you can add left tabs on the ruler for how deep the tabs will be in parts of inches. Set a few.

This will only apply to new documents. Under Documents/convert/convert to default style will let you change already written lines.