1) You need the CPS, which is purchased from Motorola after establishing an MOL account. Subscription is something like $350 for 3 years.
2) Also need a good laptop and factory programming cable.
3) Also need some basic knowledge of how LMR radio works. It also helps to have some familiarity with the metaphor of Motorola programming, which has changed a tad over the years.
4) For conventional radio (i.e., non-trunked), no ID or password needed (unless prior owner of radio password protected it, in which case you need the password from him).
5) For trunked radio, you will need a valid UserID and a valid System Key file, both available only from the operator of the trunked system.
6) You start by reading the radio and saving the file to disk under something like "#### As Found," where ### are the last four digits of the serial number. Now read it again and store it again, this time under the default file name (which is the radio serial number). At this point, you edit the second read file. (You do not start with blank sheet, as is done with some other radio makes and models.) My advice is not to modify any parameter you don't understand.
I don't think you're going to learn anything about OmniLink. This is a trunked radio feature and you won't be able to program any trunked parameters without the System Key, which you're unlikely to get. In addition, OmniLink is basically a system controller feature, not a subscriber feature.