Adding a Paypal button? how hard can it be?

Hi. I have read numerous posts on this forum relating to adding a paypal button to a form but nothing seems to answer my question.

Simply i want a form that does something like this...

Who do you want to donate to?
How much do you want to donate?
Then a donate button

It should be really easy but there appears to be no information about this.

I have setup the forms
I then checked the checkbox next to the form name in the form manager
I then clicked on the redirect plugin.
I then need to enter the field names. I don't really know what these are. I saw on one post that someone put things like... currency_code, item_name, amount etc. Is this along the right lines?
I added target url as https://www.paypal.com/it/cgi-bin/webscr
I then went back into the form configuration and selected the redirect plugin. I don't know if this is on or off. Ive read in the forum that it has to be green but then why is there a "X" next to it?


I have tried to then submit the form but i get an error message...
"You are not allowed to access this URL"
I then turned the checktoken option off but then nothing happens.

Am i missing something? Is there not a straight forward tutorial i can look at?
Is it something to do with the https: ?

You help would be greatly appreciated
Thanks

i turned on the debug info and got the following error...
Message

* $_POST: Array ( [select_1] => Current Appeal [text_6] => 67 [button_3] => Donate [277ac3bed5118d36ca2f6e1d760a7388] => 1 [1cf1] => 74991c5984e6fdbdc780611dd1ef2ef0 [chronoformname] => Donate )

i dont know if that helps.

ok. i managed to get it working. Only problem is i don't know why. I tried it again 5 mins later and it went to paypal. I don't recall changing anything. ;-)