Next link on product page

You just need to turn off the "random" option of your menu/module. That way, the products won't be randomly displayed and a pagination will appear if necessary.

You can follow the instructions on that page: www.hikashop.com/support/documentation/8...ling.html#pagination
For the position of the pagination (top or bottom of the listing) you will find the option in the configuration under the tab display in the latest version of HikaShop.

It should be centered automatically if you use the latest version of HikaShop with the default CSS.

Otherwise, you can use some CSS to center it:
.hikashop_products_pagination ul.pagination, .hikashop_subcategories_pagination ul.pagination{
text-align:center;
}

Could you provide a link to that page ?
Your template CSS might be interfering and thus it's impossible to give a solution which will work all the time without seeing the CSS directly with Firebug.

You can add the code:
.list-footer{text-align: center;}