Hi @Shalabh_Suman,
To expand on @Sirtaj-Singh's answer a bit, you probably shouldn't mix multiple runs.
DADA2 is meant to operate on a single run at a time (it builds an error model for each run, so mixing runs will just confuse the model and the way it picks out the ASVs).
Once you are familiar with the moving pictures tutorial, you should check out this one, which specifically deals with managing multiple runs.
Let me know if you have any other questions about this!