Configure PAgP between SW1 and SW2. SW1 should actively try to form an Etherchannel and SW2 should only respond to requests.
Configure LACP between SW1 and SW3. SW1 should actively try to form an Etherchannel and SW3 should only respond to requests.
Configure an Etherchannel between SW2 and SW3. You are not allowed to use any protocol for negotiation.
Configure the etherchannel between SW1 and SW2 to use destination MAC address load-balancing.