stand on which to replace goblets after drinking
坫 centers on a small earthen stand or platform, specifically one used to hold goblets after drinking in ancient ritual settings.
坫 combines 土 (earth, soil) with 占, which likely contributes a phonetic element. The character originally referred to an earthen stand or platform, consistent with the soil radical.
The left side 土 is earth or soil, and the right side 占 looks like a small table or stand. Picture a simple earthen stand made of packed soil where goblets are placed after drinking.
For テン, imagine ten goblets lined up on the earthen stand: ten -> テン, and the stand holds them all.