Don't sand first, you want to keep the edges. Splinters are fine to remove by making a pass along the edge.
it is important to keep things square when assembling. Without clamps, try painter’s tape to help you wrangle pieces into position. A small sized brad can be used to pin it, don’t hammer it in all the way so that you can pull it out with pliers to make adjustments.
Without a set of clamps, try a web clamp like below. They are under $20. If all else fails use a rope and some blocks.
Buy a square from the hardware. It’s good to be able to set 90 degree angles.
it is important to keep things square when assembling. Without clamps, try painter’s tape to help you wrangle pieces into position. A small sized brad can be used to pin it, don’t hammer it in all the way so that you can pull it out with pliers to make adjustments.
Without a set of clamps, try a web clamp like below. They are under $20. If all else fails use a rope and some blocks.
Buy a square from the hardware. It’s good to be able to set 90 degree angles.