Installing webbrowser and email client via Guix package manager

[Meikel]

Hi folks,

I'm interested in playing around with Guix. I found that "The Guix 
package manager can also be installed on top of a running GNU/Linux 
system" and so I followed instrunctions in

https://www.gnu.org/software/guix/manual/en/html_node/Installation.html#Installation

Now I'm able to run something like i.e.

  guix package -i mailutils

which works. As a use case I'd like to install a webbrowser and an email 
client (i.e. Firefox and Thunderbird or something else) so that I'm able 
to browse the internet and read my emails with software that was 
installed via "guix package -i". I'd like to run

  guix package -i <webbrowser> <emailclient>

but I have no idea of how to find available packages for such software 
like webbrowser or email client.

Can someone point me to where to find documentation about how this can 
be done?

Regards,

Meikel