Hi! I'm a current student at UAL foundation at LCF.
To start, it's usually a week or two ish ruffly when you'll get an email asking you to submit your portfolio. From there, you have ruffly 10 days to a 2 weeks after you get your email to submit you portfolio. Each date varies and it tells you on the email you get.
The max amount of pages you're able to present are 25.
And sadly, because of how competitive CSM is, especially womenswear is, submitting to BA without doing a foundation year or having previous years of art school means that it's unlikely that an applicant would get in. Being in UAL, it's really competitive to get into BA and everyone's working their best to get in.
But, if you're portfolio is good enough, they might instead give you an offer to their foundation course, which is also very competitive and I high recommend doing because it opens up so many different perspectives and opportunities. Also, some say that their foundation year was their favorite year. I personally don't like my LCF foundation a lot but I bet the CSM one is a lot different.
Hope this helps and the best of luck!