First of all, welcome to the forums and hope you enjoy your stay 
Now, you asked for a guide. Here it is: The Carnival - A Guide to Pets 
You can use the online link or download the entire thing for offline use. Do note that some places have blocked Zippyshare (the host for the file download) and you might need to use a VPN (opera browser has an inbuilt one) if you are getting an error.
Read it and you will find the info you need on how to get it started and level it to 100. After that, it is just a matter of farming the required items and transitioning to the complete build 