How to custom theme ?

Hi there,

you can use some CSS to style the P tags in the right sidebar e.g

#right-sidebar p {
    font-size: 14px;
    font-weight: 700;
}

How about font family ?

i want to set the style font family like the site too

then add the font-family: 'my-font-name'; property to that rule.
The font you wish to use must be already being used in the Customizer > Typography settings somewhere for it to load.

You may want to study this site, it covers the basics of CSS:

https://www.w3schools.com/css/css_font.asp

How to show LOGO PICTURE in navigation menu ?

This document explains:

https://docs.generatepress.com/article/navigation-as-a-header/