Should you vote above the line or below? And more importantly, what’s your favourite lettuce? Read on for the ultimate election guide

Scott Morrison has visited Government House in Yarralumla to advise the governor general, General Sir Peter Cosgrove, to dissolve the 45th Australian parliament and issue the writs for an election to be held on 18 May.

It comes just days after the government released its budget, and sets the scene for a campaign that will run through Anzac Day and school holidays in some states.

Well, yes, but the campaign has been under way for some time. Haven’t you been paying attention? Budgets are usually handed down in May, but this year it was brought forward to 2 April. The early budget allows the Morrison government to campaign on its changes to the low and middle-income tax offset and its promised $100bn spend on roads and rail infrastructure.

But it also gives the opposition the same opportunity. In his budget reply speech last Thursday, the Labor leader, Bill Shorten unveiled, a $2.3bn package to reduce out-of-pocket costs for cancer patients and promised more generous tax relief for workers earning under $48,000.

Even earlier than Tuesday though, the Coalition’s slim hold on the House of Representatives means the 45th parliament has often felt like one long campaign. The only difference now is that we know where the finish line is.

Organised chaos, really. Corflutes in front yards, awkward photo opportunities, zingers, the Bill Bus, the ScoMo Express, and a chance for our politicians to demonstrate just how totally normal and well-adjusted they are. With any luck one of them will absolutely lose their mind eating a meat pie, and Shorten will treat us to his famously unforced patter. What’s your favourite type of lettuce?

As mentioned, the campaign will run through school holidays in Victoria, New South Wales, Queensland and South Australia, as well as Anzac Day on 25 April.

Yes, vote. It’s compulsory in Australia, so if you don’t you could receive a fine. If you haven’t enrolled, you can do it online here. If you aren’t sure whether you’re enrolled, or what electorate you live in, you can check your details here. According to the Australian Electoral Commission the deadline for enrolment is typically at 8pm seven days from the issuing of the writs, so get cracking.

When you head to vote on polling day you’ll be handed two sheets, a small green one for the House of Representatives and a large white one for the Senate.

Federal elections in Australia use a mandatory preference system, meaning that on the small green sheet you’ll need to number all of the boxes in order of your preference.

Once polls close, first preference votes are counted. If no single candidate secures an absolute majority, the candidate with the least number of votes is eliminated from the count.

The votes for the eliminated candidate are then redistributed among the remaining candidates starting with the number two preference. That continues until one candidate has a majority.

In the Senate, you have two options. You can either number at least six boxes for your preferred party or candidate above the line, or vote below the line for individual candidates. If you vote below the line, you need to number at least 12 boxes.

Unlike the house, Senate voting uses a proportional representation system to ensure the right amount of Senators are elected from each state. It means political parties are represented according to their share of the vote and tends to make the Senate more evenly divided between the major parties. It also often makes it easier for minor party candidates to be elected.

The economy, climate change, immigration, health and education are expected to be the major election battlegrounds.

Both parties put tax cuts at the centre of their budget and budget reply pitches. Treasurer Josh Frydenberg’s first budget included $158bn in income tax cuts over a decade, while Labor countered with its own cuts for low-income earners.

The Coalition sought to use the budget to blunt Labor’s advantage on health by ending the freeze on Medicare rebates, but Shorten’s announcement on cancer treatment funding will likely claw some of the advantage back.

On climate change, Labor says it will try to implement the national energy guarantee abandoned by the Coalition, with a higher emissions reduction target – 45% by 2030 – as well as a national electric vehicles target of 50% new car sales by 2030.

The Coalition plans to reduce emissions by 26% in line with its Paris commitments, largely through re-booting established programs, including $2bn over 15 years for its emissions reduction fund, using carry-over credits, and investing in renewable projects such as Snowy 2.0.

Education is another area where the parties at odds. The Coalition had sought to unpack special deals made with individual states during the original Gonski deal, but both parties have since caved to the Catholic and Independent sectors. In October Labor announced it would invest an additional $14bn in public education.

I’m not an oracle, but polls have had the opposition Labor party ahead of the Coalition for some time. The latest Guardian essential poll had Labor comfortably ahead on a two-party preferred basis, 53% to 47%, although Morrison remains preferred leader over Shorten.

That margin is broadly reflective of the way polling has been trending for months. In March, the Coalition lost its 50th consecutive Newspoll by a margin of 54% to 46%. Although 39 of those were recorded when Malcolm Turnbull was prime minister, the Coalition’s fortunes have not improved since Morrison took the job last year.

They’re now banking on the budget – and the coming campaign – to save themselves from electoral wipeout.