I've been awhile now thinking to create my own PC Games CD-Keys store. I've contacted a CD Key Wholesaler and they given prices and everything that I need. But I don't know how to deal with other methods.
How do I work on Terms of Service and policy ? Return/Order Cancel ? is there any guide or anything to help me solve this ?
To set up the Terms of Service you would want to follow this guide. Once you add your Terms of Service text I would also recommend making it into a page by doing this. After that, you'll need to decide where you want to put the Terms of Service page. Most put it into their Footer by doing this.
If you want customers to agree to your ToS before paying for their items, you can set this up by following this guide.