hello, i just joined that jam - first try ever, so not many clues :o/ and issues with getting access on discord at this time ...do i need to report there or anywhere before submission or can i just upload stup at the end of the week here?
i write in html, css and javascript - does the system here then process these files as i upload them or is there anything i need to consider?
and .... is it allowed to (re)use animations or code-snippets i have made before now?
i would be glad to read an answer as i started already and enjoy first steps :o)

You don't need to report anything in the discord server, it just a place where people can vote for the themes and talk. 
Yes you can reuse code snippets and animations. The main thing is that you shouldn't just upload a already made game (unless the theme says so).
You should just need to put you files into a .zip archive and upload it that way.

I hope this helps :)

thank you and sorry for the pressure through the timezones  - and yes, your answer helped me to calm down and relax again :o)
i was impatient yesterday but that finally made me actually read a bit more about 'how to & stuff' around itch and gamejams, still not really clear with all, but i start to see a bit through the fog...
and well, just in case i did take screenshots of my coding steps  and first styling (with the date & time of my pc :o) ... so i suppose i will use them for a presentation at the end.
discord really doesn't seem to like me ,  but as you say i don't need it, i might be able to live with that ...

thanx again, enjoy whatever