Thinking about fixturing and how the parts will be made before starting into the detailed design is a very good idea; almost revolutionary. Now if you tell us you are an engineer you will no doubt be responsible for numerous heart attacks.
Not that I have anything against engineers but so often how something is made is left until the very last thing considered.
Now having avoided answering your question I will get serious and say I do not know of any online source that will give you suggestions on fixturing. This question has come up several times and I cannot recall anyone providing any links.
When you have some preliminary ideas post more questions with pictures and you will likely get specific suggestions.
An open mind is a virtue...so long as all the common sense has not leaked out.