Generally people put multiple ideas on one Request thread, as it was said we are only allowed 2 threads per section. It is up to you on how you want to use those threads really. Some people if they don't have a lot of ideas only put one at a time. But like me where I usually have multiple ideas out there, I use those threads to split them up in the way that best fits myself. I split my stuff into Long term, and short term ideas. That is what works best for me, and I don't always use both. Others will split the two into Original ideas, and Fandom. Others use it other ways. So however you think you can best use them for yourself, is good. Or for right now, you can throw everything into one thread until you get a better handle on things also.
As we can bump every day, they limit to 2 threads so it doesn't make a mess of things and others Request Threads do not get overshadowed by because they only have one idea, and someone else might have many. Plus I find it easier to keep it contained into a smaller amount and adjust as I go.