First you need an extra account for each Bot you want to set up.
See How do you prepare a Bot account - SL account settings.

You have to do that steps one time:

Install the Microsoft Framework 3.5
Install the PikkuBot client (GUI)

The PikkuBot_Installer_VERSION.exe installation package contains all necessary files.
You only have to double click it to run. The path will queried.

After the installation the PikkuBot will automatically create a link in the Start menu to the PikkuBot directory!

• Start the PikkuHelper.exe… thats the tool to create links (shortcuts).
  
• Create one link for each Bot.
  
• Fill out the required information and check “use Pikkustarter”.
  
• After that click on “create link”. When created all links for all Bots then exit Pikkuhelper.
  
• Pikkuhelper adds for each Bot two files in the Bot directory on your harddisk: one *.lnk and one *.exe
  
• → Just use the link to start your Bots (doubleclick on the link)
  

• Create a shortcut by using Pikkuhelper or create it on your own using following parameters:

PikkuBot.exe Bot-Firstname Bot-Lastname Bot-password Master-Firstame Master-Lastname

Start >> execute >> cmd.exe
cd [Bot directory]
PikkuBot.exe Bot-Firstname Bot-Lastname Bot-password Master-Firstame Master-Lastname