/diy/ - Do It Yourself

Sup lads. Long story short I am looking to build two of these oxygen sensor simulators based on the schematic from this site:
https://www.chippernut.com/blog/o2-simulator
I have zero electronics experience past splicing wires in my car and the electronics class i took in 10th grade like 13 years ago. That being said im trying to crash course my way into this because it really seems pretty simple.

Heres my questions/concerns:
The schematic calls for 2x 1.7v@20mA LEDs. Im buying a kit off amazon (https://www.amazon.com/gp/product/B073ZC68QG/ref=ox_sc_act_title_6?smid=A2XZVOPECQVFD3&psc=1)) that has a bunch of components and stuff for beginners, and among them are sets of different color LEDs. Ive been reading that red LEDs are typically the ones that are of this spec, but ive also seen them listed as 1.7v-2.0v... How do I know which one it is? Is it safe to have a range? How do i know what the specs are for the diodes in my kit if they arnt listed outright? Ive tried looking online for a diode of this exact spec but all I can find are ones from radioshack that cost 5 dollars a piece which is retarded. The rest dont seem to list the amperage, only voltage. Again i sorta dont know wtf im dealing with so is the amperage a concern here?

Another question: can I/should i use a car battery for testing this device? I need 12-15v power source, and since itll be wired into my car, I figured the best way to test is using a car battery. Is this a stupid idea? Is there a better/simpler way to do this?

Sorry if these questions are really dumb or something, again I know extremely little on electronics. Just want to make sure im not going to screw something up and fry my cars electronics.

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