What is the ideal flow for buying on a decentralized exchange?

Ideally...

1. I visit a website. I don't need to download anything.
2. I click BUY or SELL
3. I see some options who to buy from and their asking prices 
4. I have a clear understanding of how this thing works. Don't just tell me the payment method, but how that transaction looks like after I hit buy. 
5. Sort by payment method
6. Guide me through the transaction or better yet, facilitate it automatically. 

What does the dream flow look like?

1. Click buy. You are automatically offered the best deal with your preferred payment method (maybe you specified it earlier). 
2. You are provided super simple step by step instructions to finish transaction. 

Similar for sell side. 

The issue I see with decentralized exchanges:
1. Have to download something
2. The whole thing looks way too complex
3. Not clear how it works

Compare to centralized exchange:
1. Click buy. Done. 

See the difference? 

I think if we are to improve the UX, we have to think grandma level and start from scratch. No trying to improve a complex trading platform, but really think from the basics. What will grandma need to know or click on and how will she feel about it?

You make it work for grandma. You make it work for everyone.

The issue I see with Bisq (I couldn't install it, got corrupt file) is that it looks like a literal stock trading platform. NOT for an average person. I'd say you have to strip it down to 10% basics to make it work for the average person, provided you do everything else well.