I repeat the opinion that you sound like you should have someone else do this for you. That is not an insult, we cannot all be experienced at everything. For example, I would not attempt a gasoline engine teardown/rebuild even though I know the theory.
However, there is value in knowing the basic steps so that you can make sure whomever you hire for this does it properly. A few tips:
* You must obtain an electrical permit, have this inspected, and have it signed off. Mains electrical and natural gas should be permitted. It will make insurance, home sales, etc. easier even if you don't care about safety while YOU are living there.
* If you want 240VAC, you will need two adjacent open circuit breaker slots in your breaker panel. They will receive a dual ganged, mechanically interlocked breaker of the appropriate amperage so that you get both phases (hence 240VAC) and they trip together when either phase has a problem.
* You will run four wires from that breaker box to the outbuilding: Phase A (black), Phase B (red), neutral (white), and ground (bare or green). NEC has changed recently such that you must run a ground wire even if you provide the outbuilding with its own separate grounding rod into the earth. Don't ask how I learned this. Grrrr. {Reaches for pill bottle and blood pressure cuff.}
* Those wires should probably be buried. 18 inches deep if in conduit (strongly, STRONGLY recommended) or 24 inches deep if you use "direct bury" cable (strongly discouraged). Use one size larger conduit that the specs say you can get away with, because pulling those wires through all that conduit is a PITA. Do not turn more than four 90 degree corners without a junction box to interrupt the 360 degree total (and realistically 270 is about the limit). EDIT in response to other comments: These should be individual stranded wires of the appropriate gauge, not Romex with an outside sheath. The conduit is considered the sheath in such installations and having an additional sheath violates NEC's heat dissipation requirements unless you dramatically over/undersize things. Just use individual stranded wires.
* You will need a small breaker box at the outbuilding. According to code it won't need its own "main" dual-ganged breaker but you should install one anyway (my opinion) because you should really have a way to kill all power without running back to the main house. It will then have a bunch of smaller breakers for the various circuits in the outbuilding, including duals for the 240VAC circuits you claim to need.
* Once signed off by the inspector, the new box in the outbuilding should receive a sticker with the inspector's signature.
Code has been changing a lot lately regarding the use of AFCI/GFCI breakers, which are about 5X more expensive than standard breakers. They're great, except when powering a arc welder which by definition creates an arc. I mention this because if you're wiring an outbuilding, and if you're talking about 240VAC, you may be thinking about an arc welder. I've had long arguments with inspectors about the insanity of demanding an AFCI breaker (or outlet) on an arc welder circuit. They simply pop all the time, utterly unworkable. Once you're finaled, I'm sure you can imagine ways to solve the problem of having arc-fault devices in an arc welder power circuit. I will leave that as an exercise for the reader.
There's lots more, but this will at least allow you to oversee the process while someone else does it. This is all based on US National Electrical Code (NEC) and as noted by others, local jurisdictions may have differing requirements. I'm sure Canada has its own version of its NEC, too. Very often local jurisdictions "adopt" some year version of the national code and then impose their own separate requirements for things about which local politicians believe they are smarter than folks who actually do this stuff for a living every day (and who write the NEC!). There are also varying thresholds for what you, as a homeowner, are allowed to do for yourself. Here in Idaho you can do anything (and I have!) as long as you get a permit and it passes inspection. But I've been told that in some cities you are not even allowed to replace a broken outlet or switch without hiring a licensed electrician. YMMV. EDIT: I just remembered one exception, even in free-wheelin' Idaho... you cannot wire in your own automatic generator switch. They really don't like it when somebody does it wrong and it "automatically" energizes the power pole wires outside your home when the line crews are trying to fix a power outage. People die that way.