Computer program downloads

cause me extreme frustration.
I just want something that says, "Click on this button to download" and then "Click on this button to make it work."
Yesterday I decided, after a lot of deliberation, that I needed a much better program than I had to make knitting graphs. 
Now I know this will seem strange to the non-knitters among you but such things do exist. Like anything else, some are better than others. 
Mine is old. It is not very powerful. It was fine when I was simply doing things for myself. Now that I occasionally have to design something that other people are going to use it has to be better than that.
So, I went hunting. (We cats are reasonably adept at that.) Then I went prowling through the reviews. I found the one recommended by a major knitting site that I trust. Yes, good reviews and apparently easy to use.  I took a deep breath - because I hate not seeing things in detail before I buy them - but there were no growling reviews so I bought the item.
And I couldn't download it. I tried multiple times and it kept stalling half way through. (It was also extremely slow to get that far.)
I contacted the site and had an almost instant and helpful response. The person at that end went out of their way to download the program to a server on this side of the world - much faster. Great!
And then I tried again. Yes, I downloaded the program. Now I can't get it to work. I need a "workspace". 
Now yesterday I downloaded something called Java. I don't understand that either but it was apparently necessary before I could do download the program. 
Now it seems I need something called Java Eclipse. I really don't understand that at all. It is starting to scare me.
I need help. I am a frustrated cat. We cats like to keep things simple! Why do humans have to complicate everything? 
I just want to get on with MY work.  Growl!