Help adding a stock item to a table.

This proposed formula solution adds two helper columns which may be moved and/or hidden for aesthetic purposes.
Helper one extracts the dimension used for placement using:

Formula:

=IF(LEFT(B6,2)="LD",VALUE(MID(SUBSTITUTE(B6,"x","_",2),SEARCH("_",SUBSTITUTE(B6,"x","_",2))+1,LEN(B6)-SEARCH("_",SUBSTITUTE(B6,"x","_",2))-2)),"")

Helper two ranks the placement values using: =IFERROR(RANK.EQ(J6,J$6:J$12,1),"")
On sheet 2 the records are placed using:

Formula:

=IFERROR(INDEX(Sheet1!B$6:B$12,MATCH(ROW(1:1),Sheet1!$K$6:$K$12,0)),"")

The dimensions are listed in column I using:

Formula:

=IF(B3="","",MID(SUBSTITUTE(B3,"-","_",3),SEARCH("_",SUBSTITUTE(B3,"-","_",3))+1,LEN(B3)-SEARCH("_",SUBSTITUTE(B3,"-","_",3))))

Let us know if you have any questions.