Ken, welcome to the forums. Making splines is easy, just cut a strip off the edge of a board and cross cut to length. Choose a standard straight or spiral up cut bit size such as 1/4" and cut your strips 1/4" wide to match. If you do this off a 3/4" actual thickness board you get a perfect sized spline. Mount your bit in your table with a fence to keep your material square and your bit height above the table set to 3/8". Pass your wood over it and the resulting slot will accept half the spline.
I will edit this later with a couple photos to show the set up.
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