Here's a basic, how to scanlate.
It may have mistakes, or there may be better ways to do it, so feel free to divulge your knowledge - no doubt there will be some who know more than me about it

I haven't done all the steps ... I even failed the proofreader test that I helped a tiny bit with creating

- but you don't need to be an expert at anything to understand the process ...
Since I also do colouring and traces there is a bit extra that happens but I'll skip that.
The manga raw has two releases: LQ (low quality) and HQ (high quality)
Most work is done from the HQ - I'll write this assuming only an HQ - which I think is correct for the manga that was under discussion.
Once the HQ is spotted I usually download it and make it available for everyone so that all the dialup and anti-torrent people can direct download (ddl) it from the archive.
Of course everyone needs to understand a simple way of identifying each bit of text on a page.
Most people know this, but, it goes right to left and top to bottom (with a few other rules for overlapping panels) but you gotta understand that COMPLETELY otherwise there will be a lot of confusion.
If you don't already have a naming strategy, an easy one is: page, panel, bubble e.g. P10 P4 B2 = page 10 panel 4 bubble 2
There is also text that isn't in bubbles, you may want to use T instead of B for them - though there are other choices

Same for SFX - maybe S?
Next the translator will do her work and post up a full translation without SFX.
The editors can also start straight away when the HQ comes out doing: leveling, cleaning, rebuilding, joining double pages etc.
This can well be broken up into X pages per person.
Obviously, no text entry yet.
Next is the proofreaders job to work out edits for the English - it's not up to the translator to provide perfect English - coz that isn't her expertise and also would be a waste of her time - she has to provide a translation that the proofreaders can understand.
Now - it's important for the translator to understand that the proofreader(s) will be changing her work and for her to not get to uptight about it ...
So the proofreaders make a list of corrections, but not to actually correct the original text, rather to list the changes
This includes grammer correction, punctuation, rewording Japanese-English into English-English and sometimes completely changing a sentence to make it easier to understand
Output can be something like this:
Page 12
-------
P6 B2: "Erruru smiled meekly."
P6 B3: add a fullstop after 'death'
While the proofreaders are doing their thing, the SFX translators job can happen. The SFX translators can be the translators or another group of people who will need some help from the translators (lots at the start and less as time goes on)
This shouldn't happen during the first translation unless the translators are not involved.
The SFX team should definitely be making a log of what kana matches what SFX in English to help as time progresses, but of course remember that it's not always consistent and often some kana will have more than one translation based on context
Once the Proofreaders have done most of their work they may have questions to ask the translators to help with the proofreading. This can happen during proofreading or after ... since after will also involve discussion between the translator and proofreaders to sort out any questions/problems with the changes. Probably after is easier to avoid problems.
Once the proofreaders and translators are happy with the edits and after the editors have cleaned, leveled, rebuilt and joined the pages - then the text can go in.
This can be done by one person since it usually isn't the longest job. If more than one is necessary (i.e. break up the pages among them) then you have to ensure consistency. Don't use lots of fonts - that just makes it look crap!
Now the SFX is still a bit of a mystery to me why it doesn't get checked after being put in - so I guess it should go in now also if you want to be able to QA it.
Next is the pre-release - same as the release but only handed out to the team to check - but really only the QA team should be necessary here.
The QA team may be the same as the proofreader team - but if you have enough, it could be a separate team - but QA encompasses proofreading as well as checking the editing (font selections, cleaning, etc)
Out of the QA comes more changes.
These changes can be stuff like (P10 P3 B5 - needs cleaning - mark at top, P5 P1 T5 - wrong font!) or more proofreading style comments or mistaken SFX changes or whatever.
QA is quite hard to do also, coz it covers checking everything.
Once the QA changes are applied you have your final release.
(Oh yeah - I actually checked that my team leader was happy with me writing and posting this)