New woodworker here looking for some finishing advice. I have already made a coffee table and fish tank stand both pieces were stained then poly applied. Now I have been asked by my fiance to build a toy box for our almost 1 year old son. I am half way through building this project and am now thinking about how to finish it. The base of the toy box is made using 3/4 birch plywood with iron on edging and a 1x4 trim around the bottom with a routered top edge. The lid of the box will be 3/4 birch ply with real wood birch edging applied around the perimeter. My fiance has said she wants the interior of the toy box to be stained a darker color as well as the top to hopefully match the floor and furniture in his room which is why I went with birch ply and wood edging for the lid. I wanted to go with all solid wood for the top but unfortunately i dont have the equiptment or experience to glue up something of that size.
Now for my question. For the interior and lid I am sanding lightly with 220 grit sandpaper as to not sand through the veneer. Then figured on applying pre stain conditioner, stain then poly. The outside of the box that will be painted is mainly where I am having troubles. I have a few places I want to use some filler to cover knots and defects in the wood but after I sand the filler I am wondering whether or not I should prime the box then paint and if so is there a certain kind of paint/primer I should be using? I am hoping for a smooth finish but would prefer it to not be so glossy. I do not have much experience painting.
Any input for either the staining of the birch and painting would be greatly appreciated.