Checkout pages issues, logout

-- url of the page with the problem -- : www.dogburtinos.com/shop2/
-- HikaShop version -- : 2.4.0
-- Joomla version -- : 3.3.0
-- PHP version -- : 5.4.44
-- Browser(s) name and version -- : mozilla
-- Error-message(debug-mod must be tuned on) -- :

Hi
I am getting problem with checkout when i want to buy items... When I am in the basket and see my top link :
www.dogburtinos.com/shop2/index.php/comp...checkout/step/step-0

then I am going to login and I can see page where i can choose one method of shipping, after when i mark and press button NEXT -> I am going to back first page of checkout:

www.dogburtinos.com/shop2/index.php/comp...checkout/step/step-0

Why is like that? also I would like to logout myself and I try to put link :
index.php?option=com_user&task=logout

but it is not working and i see blank page 404 error....

Many thanks for help

Hi
Thanks for fast answer
I have attached a screenshot of checkout

Many thanks
lukasz

Oki I got it - it was only needed module login to active - to customers can log out and end session

many thanks