You can make hard top (so you lay down your pedals first, make holes for cables - here you would need rather solderless or solder it when pedals attached) and screw the pedals to it. Or you can do Velcro on top with slots for cables. I have 2 rows of slots in 1/3 and 2/3 height of top and aditionally 2 on each side of top to get the cables from jack inputs and outputs.
It is really a matter of planning and how you want it to be in the future. Velcro top lets you to swap pedals without unscrewing them, so I think it is a bit more comfortable solution.