How to put widgets on my home page

Hi all,

Please first check this website that is using the FULLSCREEN template.

https://www.meicw.com/blog/

Quite the same way as seen there, i would like to set up on my future website, an access to categories, pages, search, and a contact on the center bar.

Being a WordPress rookie, i just learned that this could be achieved with the use of widgets ?

Here are the instructions you get with this FULLSCREEN Theme:

There are a total of three widgetized areas on this theme. The bottom left three-column area is 100% widgetized. The right column is reserved for credits and feeds. You can add and delete widgets by clicking Design – Widgets, from within your WordPress admin panel.

(link to the the FULLSREEN Theme)
https://graphpaperpress.com/themes/fullscreen/

My website is for now intalled ”locally” on my PC, with no more than 3 test posts, in ”Uncategorized”…

I gave a try to install 2 widgets (a new category and a search box) with Wp-admin on my site’s dashboard, but the problem is that once installed they appear at the bottom of each of these posts page.

So how to get those on my homepage ?

Thank you Very Much !