Minecraft wiki entry for Redstone_computers, associated text: The player may want to use mods or data packs like WorldEdit.
Color code your computer (use blue wool or concrete for RAM, yellow for the ALU, etc.)
Start small, and get the hang of small computers before you try more complex machines.
Structure blocks can be very helpful for moving components around, and combining multiple components together. However, note that these cannot be obtained without using commands.