About this 3D model

This is my first atemp with remixing, pls don't judge, constructive criticism welcomed. This is a remix of 7 Multiholes, Push-Fit Shelf from Multiboard “streched” to my needs. Changes include: 2 multiholes longer than the biggest one i found. Overall length increased by 50mm 23 mm deeper Part that goes in to multiholes is 3 mm longer so it's flashed on another side of the Multiboard. Has only 1 hole space instead of original 2 holes spacing.