after? first thing first figure out the cpu and mobo are compatible. dont buy a ryzen with an intel mobo… then figure out if your ram is compatible (check if your current ram is the right ddr. if its ddr3 and you buy a ddr4 board, they will not work with each other.
also check if the gpu and cpu you buy are good enough for what you are doing. (gaming, workstation, server ect.)