Combine Clips - Joining Clips

It must be very easy .. But two days (serious) i couldnt find an answer.. How can i combine two clips as a single clip..

I have 16 clips on same track as sequential, I try to apply effect (changing speed of all of the clips) ..
So very simple solution is convert 16 sequential clips to one single clip and then apply what i want .

But there is some problem ! I couldnt combine any clips ,
am i missing something or Its premiere's problem ?


(Apart from this subject ,i try to make mixed clips time to time accelerated)

Thx for advice ..