Yeast harvesting

I was wondering how I can start harvesting my yest from my fermented beer. I have an oatmeal stout that has been in the primary for a week and a half and I plan to start to cold crash it after 2 weeks. So after I siphon my beer in to my bottling bucket, I'm left with my yeast cake, hops, and trub. Do I just get a mason jar sanitize it and dump that stuff in to the jar?

How much is good for my next batch? as in cups or ml

Should I then make a yeast start from this?

Btw the carboy that the stout is in has a bunch of krausen still stuck on top near the airlock. So I don't think I would want to rack my next stout in to this carboy... anyhow its only a 5 gal one and I now have a 6 gal one open that I would rather use.

Thanks!

read the sticky on yeast washing in the yeast/fermentation forum. All you need to know

Thanks for pointing that out I had read about 20 pages so far and I am still concerned about collecting a bunch of hops when I wash my yeast. My next batch of beer will have 4 oz of pellet hops in it.

Don't worry. They will "wash" out. Do it a couple times and give them time to settle. By the way, I put my hops into a muslin bag and tie both ends off. I've used cheese cloth in a pinch. Just make sure it is large enough to let the pellets expand.