How to add 2 sets of data into 1 table cell array ?

I have 2 sets of data (FinalLP_FullLoadProfile_BeforeNorm and AbnormalityCusAssump). i try to add some part of these sets into a same column of table cell array name "Datapreparation " by this code

   for yy0=1:498
        Datapreparation{yy0}.Var3(1:892) = FinalLP_FullLoadProfile_BeforeNorm{yy0}.Var13(1:892);
        Datapreparation{yy0}.Var3(893:end)= AbnormalityCusAssump{yy0}.Var13(893:end);
end

Where these three table cell array (Datapreparation, AbnormalityCusAssump and FinalLP_FullLoadProfile_BeforeNorm) have a same number of rows. However, when I perform this code, the software show this error

"Undefined operator ':' for input arguments of type 'cell'."

How can I fix it to complete my goal ?

Thanks in advance

[Walter Roberson]

Could you confirm that Datapreparation is a cell array with 498 cells, each entry of which is a table() object that includes a variable named Var3 ?