Here’s your idiot’s guide (written by a bona fide idiot).
Most votes at a general meeting are by a show of hands unless someone at the meeting demands a poll vote which means the vote must be conducted according to Unit Entitlements (UEs).
All special resolutions must be conducted by poll votes (UEs).
Committee elections are to be conducted by owners writing the names of their preferred candidates on an otherwise blank piece of paper. The default is one vote per lot but any owner entitled to vote can call for the election to be by a poll vote.
All committee votes are by a show of hands – UEs, proxies and the number of votes by which the member was elected are irrelevant.
In the case you mention, minor renovations can be decided by a show of hands, but major renovations requiring common property by-laws must be by a poll vote. Sustainability or accessibility by-laws require a special resolution by poll vote but they only need a 50+ percent majority, not the 75 precent normally required for special resolutions.