First steps for me is always the landing gear so the plane can sit on the workbench by itself. Should be straight foward but provided the first hiccup of the build.
I like to get things as close to perfect as possibble (fits the description of most pattern fliers.) In order to make sure both gear halves are aligned the same way I extend a line on my building table from a typical green cutting mat with a 1" grid on it. With the tail and the nose on the centerline I can check that both gear are equally placed on both sides of the fuse. See the first 2 pictures.
This is my third electric build so I have learned to try to save weight whenever possible. This will often add up to an ounce or two when done. The supplied steel cap screws, washers and blind nuts for mounting the gear weigh 14 gms. Switching them to aluminum cap screws and aluminum washers with a standard 6-32 blind nut brought the gear mounting hardware down to 7 gms. Blind nuts were glued into the landing gear plate from the inside.

The wheels and wheel pants are next. The supplied steel axles and nuts weigh 13 gms (a bolt for an axle, 2 nuts and a nylon accorn nut for each side). I prefer NMP aluminum axles (see pics).Weight is only 5 gms complete. The wheel pants will take 2 1/4 to 2 1/2" wheels.
I chose to go with 2 1/2" Dubro lite flite wheels which weigh 23 gms per pair. Although a couple of grams heavier than listed on the package they are the lightest of the standard sized wheels that I have found. If you fly regularly off asphalt then you will need to replace them during the season as they wear easily.
The 2 1/4 " wheels only weigh 16.5 gms. I required a spacer to center the wheel in the pant (neccessary if using the 2 1/2" wheels.) A prop adaptor from an APC prop was the perfect diameter and thickness to center the wheel. I know I save all of those extra adaptors for something
The wheelpant is held at the proper incidence by a 2nd 2/56 cap screw through the landingear and into the wheelpant. 1 blind nut on a small piece of 1/8" lite ply is glued o the inside of the pant.
Try to keep this screw as far away from the NMP axle as possible. If too close to the wheel axle it will be easier to rotate the pant. This wheel pant mounting method has worked well for me on 2 Oxai planes even when flying off grass. Of course if you fly off thick grass like at the Black dirt field in Goshen NY (they grow velcro there) you will have to remove te wheel pants
The Comp Arf gear does not have much of a flat spot to mount the wheel pant too. The 2nd 2-56 screw will pull the pant over, so it is a compromise of how far away you can put it and how much you want to deform the pant. I would prefer a larger flat area like the old Bolly gear or a molded interlock between the gear and the pant as one company makes (can't remember which).

The issue came when trying to mount the belly pan while the landing gear is attached. The rear portion interfeared with the gear already in location. Because the gear are close to the rear of the belly pan area it is impossible to slide the alignment dowles into their corresponding holes with just a slightly oversized gear cut out.
Choices would be to enlarge the rear of the cutout by 3/8 to 1/2 inch, a little bit uglier, and may weaken the rear corner of the belly pan. Cut 6 holes through the bottom of the belly pan to place the gear mounting screws, also uglier, or reverse the direction from which you attach the gear. A PIA as the gear is already mounted, but the best cosmetic result. Now if you think you will have to remove the belly pan (chin cowl) frequently then only the first option would work. Enlarge the opening. I do not see a need for the belly pan in an electric version and would prefer if they made the fuse without it for electrics. One last choice would be to mount the gear above the ply plate as you can for glow but this would require longer gear for electrics.