1. Login to your Analytics account.
2. Choose Edit besides your profile.
3. Check, that you have clicked Yes to E-Commerce Website part.
4. Choose currency.
5. Make a goal, check active goal to Yes. The goal url is
http://yoursite/funnel_G1/checkout.thankyou.htm
6. Leave Goal value field empty or type in 0.
7. Leave other fields empty for now.
If possible, make a test purchase with cash and see, if you have your order information inside a form in receipt page. It should look like this:
UTM:T|7|Joomla 13|53.18|4.05|0.00|Los Angeles|LA|USA
UTM:I|7|6|Hammer|Hand Tools |1.00000|1
UTM:I|7|5|Nice Saw|Hand Tools Hand Tools |23.14242|2
Please note, that if the payment method doesn't have a receipt page, then of course, it's not possible to track purchases with that payment method. For default paypal and cash on delivery have receipt page.
Check your E-commerce report after 24-48 hours. If your goal is working, then add funnels.