Glad to see you're trying Webflow.
Looks like you're trying to style a Rich text component.
The Rich text component is made up of other elements like headings and paragraphs that inherit global styles.
The template you are using has these global styles set for all headings and all paragraphs. That is why, you can't apply a new font to the Rich text component as a whole.
You need to style each element separately.
If you need a different style for the project page paragraphs and/or headings inside a Rich text, you can watch the following video:
or read the help text here:
You can learn more about rich texts here:
Please, tell us if this is helpful.
Best of luck,