how to install a shell on Z-5500g/ howto using as linux machine

how can I install a shell on Z? 
Is there somewhere a howto for Z to use it 
as a linux machine? 
I wont use that adress&planing stuff that is preconfigured. 
I need a shell! I want to download some data to 
my 32MB card an study the data with Opera browser 
or read big mail file while I'm on the road (public
transport vehicles). 

I wonder why Opera claims "no space available" when 
I try to download a 7 MB file. The "info" of Z 
shows 28M free internal Memory and 32MB free CF-Card
memory. How have I to understand the message of opera?
Where is the CF-card mounted? ..... and so on ...

please help! I need some pointer for first steps.
I'm quite good familiar with linux but can't cope 
with Z so far. 

I already own these pointers: 

http://docs.zaurus.com/
http://www.zaurus.com
http://killefiz.de/zaurus/showapps.php?cat=1

.. but no HowTo concering first steps!

thx
Ekkard