Re: Traditional Chinese or simplified
In general, manhua from Mainland China will be written in simplified characters, while manhua from Taiwan will be in traditional characters.
If you're referring to translated manga, then it depends on the Edited Manga group on the same basis.
Though simplified characters do look easier at first, learning traditional should be better in the long run as simplified characters will become intuitive once you know traditional, making it much easier to learn the other set of writing system. (That said, most learning materials I see are simplified-focused so perhaps you may not have much choice.)
I'm not familiar with good websites or learning material, I'll drop a link or two at the end maybe, perhaps someone in the know could give you something better. I'd say when you learn Chinese, you want learning materials that explain to you how a sentence is made by breaking down an example for you. Despite the writing being relatively difficult, constructing sentences is actually very straightforward for an English speaker, grammar generally is not complicated at all. All that's left afterwards would be expanding your vocabulary.
Also, I'm sure most learning materials do this already but make sure you learn how to pronounce the things using materials that give you both the Chinese characters and readings spelt in English. Knowing how to read aloud can help you identify the flow and key words in sentences, which can help with your learning on the whole.
I can only recommend you this link for now:
http://www.chinese4.eu/
The "Chinese for Children" section is pretty basic and breaks it down very nicely. Should give you an introduction to constructing basic sentences (they even have audio along with the text.)
"Chinese for you" section gives you a few examples of everyday conversation, although it's not something I'd recommend to beginners unless you're a tourist-to-be on a Chinese crash course. While it does give you translation to the examples, the translation is not literal enough for you to see how you can break down that sentence (thereby learning to apply that same structure elsewhere.)
Eg. This is from the "Money and shopping" subsection:
行，我买一瓶可乐。一共多少钱？
Xíng, wŏ măi yì píng kělè. Yīgòng duōshao qián?
Ok, I’ll take a bottle of coke. How much altogether?
You'd probably want materials that can break it down on a literal level like so (note that I've translated the following very literally):
[行] [我买] [一瓶] [可乐]。 [一共] [多少] [钱]？
Xíng, [wŏ măi] [yì píng] [kělè]. [Yīgòng] [duōshao] [qián]?
[Ok], [I buy] [one bottle] [coke]. [Altogether] [how much] [money]?
You'll notice the "will" and "of" are not directly present in this particular Chinese sentence. Sometimes, these English devices are not necessary and at most implicit when it comes to Chinese. Hopefully by breaking down examples like so, it would put you in a 'Chinese mindset' in order to tackle other sentences.
When it comes to finding materials that take apart sentences like the above, my money would be on the typical textbooks you find at the bookstore, to be honest. Try reading through the books first to see if their teaching style suits you. Regardless, most beginner-orientated materials usually have well-planned chapters that take you through your learning logically.
