You need network cards (and drivers) and a managed switch that will support it. Do you know what NIC's / switch you're using? You'll need to enable LACP / 802.3ad on the switch ports and then setup your NIC software per it's instructions.
This can be kinda confusing as there are about a million different keywords you maybe looking for when setting this up on both the NIC's and the switch, some vendors call it different things:
LACP (Link Aggregation Control Protocol) aka Link Aggregation
Good luck, if you can post the hardware you're working with we maybe able to help confirm it supports it.