what order should the lessons be completed in?

Hello,

I am struggling with this, I am trying to learn things. I think the tactics lessons jump a lot in rating. Some one suggested that I learn nothing but tactics while I am rated under 1000. So I started on the tactics lessons. I have completed the first 4/5 courses when the rating level is set to "Average". I finished the course on interference which I found very difficult, then trapping which was not so easy. I think these are at a 14++ rating, which is a little high for me. 

So, should I continue as is or go to something else?

Continue with the tactics as advised an as for the lessons, if you do one that's difficult to understand go back to it again. Try to really absorb and understand the material. It may take several reviews of each lesson to thoroughly understand them, but it will help. And don't rely solely on chess.com! If you find one of the lessons difficult and you need more information on the topic, search the web for the topic in question. There's tons of information out there. Also, don't hesitate to ask us here in the forums about it. You'll get some stupid responses, sure, but I can nearly guarantee you that someone will always answer your questions to try to help you better understand. Hope this helps.