Minecraft Bedrock How to use /fill command

/fill coordinates block id# (replace,outline,destroy,hollow,or keep)
Replace changes all blocks in designated area
Outline changes only the outer blocks
Destroy changes all blocks, destroys them and drops them, then fills in the area
hollow changes all blocks inside the area to air while changing the outer blocks to the designated block choice
keep only changes air blocks to designated block choice
Music:
Superhero NCS by Unknown brain
Heroes Tonight NCS by Janji