How were the Israelites to apply the blood to the door in Exodus 12:22?

Les explains that Exodus 12:22 gives the explicit instructions for applying the blood, and it had to be done in a particular way, not just any old way. The Israelites were to take a bunch of hyssop, dip it in the blood in the basin, and strike the lintel and the two sideposts with the blood. Hyssop, Les notes, was a little bush or weed that grew everywhere in Goshen, which he likens to ragweed. They dipped this common weed into the basin of the lamb's blood and applied it to those three places on the doors and on the lintel. Les also likens hyssop to the work of the Holy Spirit: because hyssop was everywhere, no Israelite could claim he had no chance to find it, just as no one can say the Holy Spirit never worked in his life. The Holy Spirit is omnipresent and gives every person opportunity to accept or reject God's salvation. The verse also says none were to go out of the door of the house until morning.