Riva is very popular. I have a couple and I recommend the one you listed for the 3-click enable/disable
I would only buy that at Liberty-Flights because they have the 3.7v ones. (unless the vendor you are looking at states it is Eastmall-made or the 3.7v model - that is what I recommend and what LF has). Since it's the SE and has the 3-click chances are it is 3.7v (unless some other clone maker is just copying Eastmall's popular model names and features)
You need to add 1-2 atomizers (for testing juices, vaping thick juices) and a drip tip
I would add another pack of cartomizers (perhaps 3 ohm to learn on, then go to the hotter 2 ohm ones) and PLENTY of thin high PG juice because thick VG juice is much harder to use in cartomizers (hard to get into them and the juice may move too slowly in the stuffing to keep the hot coil area damp and you would singe the carto)
Actually add several packs of cartos because there is a learning curve to not singeing them, especially if you are going to blindly shove juice in. Make sure you get 1ml of juice into the carto. Settle the carto on all sides and ends (about 15-20 minutes of doing that is enough for 80PG/20VG juices).
And keep it damp. Using a plastic or delrin drip tip as mouthpiece instead of the endcap can help - you can pull that out and check if the stuffing has gone white on top and could use juice. I also add juice any time the vapor or flavor gets light or tastes the slightest it off, before starting a freshly charged (hotter) battery, before leaving the house, when i get home, before bed, and anytime the the carto is getting unusually warm. In between, anytime I've been vaping for a while without adding any juice, I add juice. I stay away from dark, cloudy or opaque juices that drop flavoring sediment in the stuffing - you will find the sediment clogs up a carto and shortens its life. With thin clear juices I can get 10+ days use (or about 20ml run through) out of a Boge.