Depends on the pedal exactly how to remove, but there are two main methods.
You need to look closely at your pedals and see what they have. I've searched but its not visible on any website/review.
- Wrench flats on the side of the axle allow a spanner. These are often 15mm apart, so a 15mm open-ended spanner may work, but a proper pedal spanner (wrench) is thicker than a cone-spanner but thinner than an adjustable spanner/crescent. They're often longer than a normal hand tool, for added leverage. See photo:
- Hex driver in the end of the shaft - this is common on clipless pedals. The size is often 8mm or 10mm, with bigger providing more torque and also more weight saving. A pedal thread is 9/16" or 14.3mm, so a 12mm socket is very unlikely, that doesn't leave a lot of metal. You might find weird sizes like 9mm or 11mm, so make sure the tool has a good tight fit before applying leverage.
Some pedals have both wrench flats and a hex socket, doesn't matter which you use.
If you don't own hex drivers, then buy a decent set of P-handle ones with 2/2.5/3/4/5/6/8/10mm. Avoid buying one tool at a time, that's the most expensive way to acquire tools. Personally I've never been able to remove a pedal with a multitool - there's simply not enough leverage.
The single most important thing to know when replacing pedals is the THREAD is left-handed on your LEFT hand side of the bike. So the common "righty-tighty lefty-loosy" is opposite when you remove the pedal from the non-chain-side of the bike.
And the followon is that if you use a hex driver on the inside of the crank, its also reversed. So slow down and think before you add a lot of torque, lest the problem get worse by stripping a thread.
Reassembly/refitting a pedal:
- Use grease or assembly lube on the threads.
- Make absolutely sure you're putting the right pedal on the right crank, and the left pedal on the left crank
- Make completely and utterly sure you're not cross-threading. Easy to do, and will ruin the crank arm.
Further reading: https://www.parktool.com/blog/repair-help/pedal-installation-and-removal