H wrote:What other forms/applications do I need to make?
You don't need to do anything, at least in theory. You should register with a number of local places, though: the council for council tax and the electoral role, a local GP will register you with the NHS for "free" treatment, and you can apply for a National Insurance number at a job centre (although your employer can also do that).
What is a EEA registration certificate?
It is a mostly useless piece of paper, that the Home Office takes about three months to issue, and they may lose your passport in the process. I have one, but I have not found a single use for it. You can certainly do without one.
How long can I stay? -I'm going to look for work.
You can stay at least for 3 months. After 3 months, you are fine if you have a job or sufficient funds. Otherwise the Home Office may declare that you are not likely to find a job, ergo you are not looking, and you have to leave. That is not necessarily correct, but it is worth keeping in mind.