welding

1- The need of any code or standards is first to avoid people building dangerous things and second to assure the engineers are using the updated technical information available.

2- Do a google search and you'll see a lot of descriptions. By he way, have you heard about books? They are old objects that ancient people used to read, they are usually available for sale in old shops called bookstores. They are usually rectangular in shape, come wit several pages made of paper that are articulated in the middle. You'll find information printed in the pages (sorry, they are not connected to internet, but have the advantage of not requiring power to work). If you don't want to buy one, you could go to another old style place called library and search for one regarding what you're interested in.

3- You can find some references in the standards. The WPS is a document that describes integrally all the aspects covering a specific welding procedure in a production line, maintenance action, or so.

Sorry if I sound rude, but, by your questions, you need to do your homework (like all of us have done before), or you'll really need to hire a professional to set a production line.