In order to craft the Tier 4 Altar you will need to craft 4 Bloodstone Bricks, these can be crafted by combining a Weak Blood shard with stone, you will get 16 per craft (this could be different in your mod pack), you will only need 4 unless you are planning on making more altars.
Just like the previous Tier, you will need to go out one block and down one block from the altar, surrounding the Altar in an 11x11 ring, the 3 corner blocks do not matter and can be anything you want. You will also need to build 4 pillars on each corner 5 blocks high with the top being a Bloodstone Brick.
The tier 4 Altar will need 28 blank runes which can be replaced with any rune that will fit your needs. Ensure you use the Divination Sigil to ensure you have built the Altar correctly.