While doing the final R' D' R D moves, the rest of your puzzle will look scrambled. As long as you finish the full sequence for every corner, it will magically resolve itself at the very end.
Do you have a on the last layer that isn't working with these algorithms? How to Solve a Megaminx! [Beginner Tutorial] megaminx-solver-cheat
If you get stuck on a specific case, JPerm's Beginner Tutorial is widely considered the gold standard for visual learners. While doing the final R' D' R D
This swaps edges until they match the side center colors. Hold one correct edge at the 6 o'clock position to rotate the others. Algorithm: U R U' L' U R' U' L How to Solve a Megaminx
Instead of a 4-point cross, start by forming a 5-point star on the white face. Align each edge with its side center color.
The last layer (usually gray) is where you can't just wing it with 3x3 logic. Use these four specific steps from GANCUBE's Official Tutorial and other experts: Algorithm: F R U R' U' F'
Continue building "tentacles" out from your solved white face. Solve the next set of faces (yellow, dark blue, red, etc.) by forming stars and inserting corners/edges. Think of each new face as a 3x3 that you are solving layer-by-layer. Phase 2: The Last Layer "Cheat Sheet"