SIM integration help

[blind2uriz]

I'm having loads of trouble understanding the process here for using SIM integration payment option, as well as creating a form to do so. I have no experience in online payments and have never created a form to do so. If i'm doing SIM integration, can I just use the hosted payment form on authorize.net's website? If so how to I go about accomplishing this? All I want is a "Click here to pay your bill online" button on my clients website where the customers can go to the payment form(something that looks like the virtual terminal form), and enter their account #, credit card #, address, contact info, and payment amount of their bill. Under "Transaction Format Settings" you can go edit the payment form. How do you get to that payment form? B/c I see where there is a place to customize the form, i.e. header and footer. I want to add my clients logo in the header and go w/ it that way. For now, they just want a simple answer for an online payment option. Struggling to grasp this concept. Thanks for any help. 

[Scott5859]

There is a warning at the bottom of page 29 in the SIM_guide.pdf. It states that the merchant’s “transaction key” should be “stored securely and separately from the merchant’s web server”.

I don’t understand how this is possible since the sample code for C# (https://github.com/AuthorizeNet/sdk-dotnet/blob/master/Authorize.NET/SIM/SIMFormGenerator.cs) requires the transaction key as a parameter in it’s OpenForm method.

Is it good practice to save the merchant’s transaction key on the merchant’s server if it is contained in a class?