There weren't construction workers, there were priests, neighbors, gold smiths, officials, daughters & temple servants all involved in the repairs, they all had a part to play in it.
Likewise, today we all have a part in sealing up the breaches where the enemy comes in to attack the family of God. Our shovels and trowels have just been replaced by the word of God, prayer and ministry.
The place that you are called to build up may be families, teens, children, women, men, drug addicts, sex trafficking, abused, elderly and so on. Be prepared to jump in and tear down the rubble first though. You must to have a solid foundation to rebuild on. It may take time to uncover all of the lies of the enemy and replace them with God's truth. This happens through love and relationships. Genuinely caring and pouring our lives into those God places in our lives is the best place to start.
Remember also that the inhabitants of the city were not working on the barrier because construction was their trade but rather they saw the need for and value in the safety the wall provided and they were willing to jump in and be a part of it rather than say "oh that's not my job". Many of them just worked in front of their homes & neighborhoods, others took on greater responsibilities. Be open to hearing from God what your part is and willing to follow through beginning with what is right in front of you. We are all called to build the kingdom of God.