The old creation, seventh-day sabbath memorial was typological of the creation (Exodus 20:8, Genesis 2:2-3) and redemption (Deuteronomy 5:12-15). Both of these things ultimately pointed to Jesus Christ who ushered in a new creation (2 Corinthians 5:16-17) and worked to redeem His people. Upon resurrecting and walking out of the tomb, redemption was accomplished. Thus Jesus ceased from His works (like God in creation) on the First Day, where he entered into His mediatorial rest for His people (Hebrews 10:12). This is what Hebrews 4:1-11 is describing.
It mentions three types of rest—God’s rest in Creation, Israel’s rest in Canaan, and our eternal rest in Christ—which all point to the same substance—Jesus. The Author compares the rest from creation with the Israelites’ rest in Canaan (Hebrews 4:1-8), and then compares both of those to the Christian’s rest in the Gospel (Hebrews 4:9-11). All three of those rests point to the eternal sabbath rest that Christian’s have in Jesus Christ. You can read more on this here.
Both the rest of creation and Canaan had the seventh day as their memorial while rest in Christ in the gospel has a new memorial, signified with a new day—the first day—representing the start of the New Creation and redemption in Christ. Just as God worked to create, and rested or ceased the seventh day, so Christ worked to redeem His people, and then He entered His rest and ceased from His works on the first day—the new memorial of the new creation.
This has historically been called the Christian Sabbath.
The day is the memorial, not the substance. The memorial points to the substance. To see an extremely detailed breakdown of this, watch our stream here.