If the wing has not been built yet....you have a choice of either strip ailerons or barndoor type.....

First of all...the ailerons will not be very effective if you don't reduce the dihedral angle.... I would suggest about 1 inch per side....

If the wing is built and it has the stock dihedral....buy a wing kit from Sig...approx $30 last time I checked...or you can cut it in half and put a new dihedral brace in it and glue it together again...not an easy task...

for strip ailerons...you can either carefully cut about a 1/4 inch off the front of the trailing edge stock or cut the rib ends off and use a piece of 1/4 inch stock glued to the back of the ribs.....you an tape two halves of a hacksaw blade together to make a slotting tool..... Then cut the trailing edge stock to length and install strip ailerons.....

Another method is to go with Barn Door type ailerons.....
I leave the tip rib....then cut the next 3 ribs at the rear spar.....
cut the trailing edge at the inside of the tip rib and the inside of the 4th rib....trim off approx. 3/16 inch from each end of the trailing edge.....

Using 1/8th inch stock.....sheet the back of the rear spars....

Cut the front of the ribs at about 30 degrees....allow for the thickness of the sheeting..... Sheet the front of the ribs....

Cut 2 pieces to match the contour of the ribs and glue to the ends of the aileron.....

I usually use Monokote to hinge these on....and use a servo for each aileron..... for hinging.....cut about a 3 inch wide strip of Monokote....or whatever covering.....for the top and bottom....
Put the aileron flush to the sheeting on the rear spar....iron the top strip on.... Flip the aileron up and lay it on the wing....iron the other strip on.....never had one come loose......