tiling a 2ft x 6ft area by outside slider
Figure out the tile grout size and draw that on the subfloor (snap line)
Then cut your board 1/4" narrower---trowel down a bed to fresh thinset--lay the 1/4" board into that and pull it you your line--nail or screw the board down.
Then you are ready to tile---the door /tile junction need to be caulked with a flexible caulk because the door sill expands and contracts a lot---
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