Hi @Viorel,
It seems that other users have the same concern as yours.
Please refer to this thread to find out the answers: Merging 2 Activepresenter Videos together - #6 by PhuongThuy_Le
Also, we want to add further information that merging videos from different slides can be very useful to edit videos continuously without switching slides.
But in case you just want to preview them, it doesn’t need to perform this step.
Hope it helps.
Regards,
Thuy