How to get rid of all the underlines that indicates a typo or too many spaces?

You can tell PyCharm what is your preferred Python style through the Inspections and Code Style sections under Settings.  The default is to warn on PEP8 style violations but you can turn this off.  It is really common to use 4 space indentation (or 1 tab char), not 2 spaces, so if you plan on working on other people's Python code you may want to get used to this now. Code menu -> Reformat Code will reformat the file according to the currently selected style.

To adjust the preferred style, go to Settings menu.  To change the general code style such as number of spaces to indent each line, go to Code Style -> Python. From there you can adjust things like indentation level, spacing, wrapping, and blank lines.

Search for 'pep' to find the setting to disable PEP8 inspections (either naming convention, coding style, or both.) There are many other Python inspection settings available there.

Makes sense to stick with conventions.