If you are the sole owner of your property you can self-nominate. If you are a co-owner, you must be nominated by your partner(s). If you bought the property as a company, then you’d need to be nominated by the directors of that company (in a signed letter). If you were a tenant, you would need to be nominated by an owner who wasn’t standing for election themselves.
You can write to the secretary or strata manger before the AGM and tell them you want to be nominated for election to the committee. Or you can wait for the AGM at which there will be a call for nominations.
After all the nominations are in, the chair should ask the meeting how many people they want to have on the committee. Then, if there are more nominations than seats, an election is held, with owners being provided with (if it’s done properly) blank sheets of paper on which they write the names of those they wish to vote for.