5 gal betta help

[starzfish]

Could I add my fish in at the same time I put in plants? Does it matter? Following @Essjay s recommendations, I will plant my tank after it is cycled.

 

[Essjay]

If you cycle the tank, then add the plants I would wait until next day to get fish simply because putting the plants in can disturb the substrate and make the water a bit cloudy. With new fish, I prefer to be able to see them clearly so I can spot if there's anything amiss.
If you decide to go with all plants attached to decor, fish can be added the same day, but do the plants first. Being netted in the shop and put in a strange tank is stressful enough without having hands messing about in the water.