Passing values ​to the sll operation

I'm new to Assembly programming and have an elementary question.

How to pass the value that is stored in $t6 as the third parameter in the sll function?

and $t6, $t3, 0x0000001F ($t6 ​​receiving the value in $t3 and 0x0000001F)

sll $t0,$t1, value in $t6