problem with FoxyProxy / I2P in Tor Browser in Whonix-Workstation

I guess im confused with the whonix default Tor Browser,

Where as I need another Tor Browser installed to be able to edit that ones proxy and leave the whonix default one for browsing dark web…

Could anybody elaborate a little more on installing an additional Tor Browser to Whonix-Workstation so that i am able to i2p on?

Maby thats my problem afterall, im using the default one which is very secure and wont allow any addons or something?

When you wrote “Tested on Tor - Hardened,” it clicked in my mind that i have the wrong version? (normally when i access the dark web, and open Tor, I see the WHONIX page with a search engine, so please correct my confusions if you can.