You have two home tabs. One is added because you have a homepage set in Admin CP > Basic Board Information.
You can remove that one by removing the home page URL.
Alternatively, if the aim is to keep a Home tab, that looks as though it is added by an add-on. Maybe the add-on has a way to switch that off, but you would need to contact the author of that add-on for support with that.
You can remove the Forums tab (and potentially some of the others) using CSS. Add the following to the EXTRA.css template:
Note that each tab has a class. The forums tab has a class of "forums". The home tabs have a class of "home" and "portal" respectively.