Procedure for applying for FLR

I am currently holding a work permit for Company A. Company B is willing to get me a work permit.
what is the procedure, can i hand my resignation to Company A after i get the work permit from Company B?
i read on the forum that the applying of a work permit is a 2 stage process, my friends told me that the first stage is granting of a temporary permit which you use while the 2nd part(stamping of passsport?) is some sort of rubber stamping the first part, is this true?

There are two stages:

1. Work Permit stage, in which your application is checked against the WP criteria. At the end of this stage, even if your application is approved, you DONT get a temporary permit. However, the next stage is triggered.

2. Immigration stage, in which the variation / extension of your immigration status is checked against the Immigration Rules. You are allowed to take your new employment only if the status variation is approved.

sounds like a process which would take at least 2 weeks or more, is that so?