The thing is by his own admission the op is not that experienced so a simple construction using screws to secure the shelves etc is a way of avoiding buying expensive kit as per my post advising a track saw and router . In hindsight keeping it simple will be more productive and will provide valuable experience for the op .an alternative to screwing through the sides could be to use bearers to support the shelves and provide additional strength and support. I’m sure Most of us when we 1st started our woodworking journey produced ugly and amateurish pieces but I bet likewise were all as pleased as punch with our efforts. My first projects were literally 12 mm plywood, pva glue and panel pins.. not pretty but they worked . You soon learn how important it is to cut straight and square and the best way to achieve this with the tools you have ..