Your hardness is very low so you do need to raise it a bit once you have fish. This will also raise the pH a bit but hardness is more important than pH. You don't have to raise it by much, nothing like what Rift Lake cichlid keepers need - they also have to add special salts if their tapwater isn't hard enough, using aragonite/coral isn't enough, and they usually use just that as a substrate to get more of it in the tank.
Bicarb - half a teaspoon in 100 litres water will raise the KH by 1 german degree. You need to get yours to at least 3 german deg while cycling. The best way to monitor this is with a KH tester. Bicarb is bicarbonate of soda which is sold in small tubs in the home baking section of the supermarket. Adding this will raise the KH fast, though it won't affect the GH. You need to use aragonite/ coral for that. But this is a slow process so boosting the KH fast is the quickest way to get the tank cycled. At the end of the cycle, you'll change 90% + of the water before getting fish which will get rid if the bicarb.
pH - some water companies add carbon dioxide to the water supply, which loweres the pH. Does yours change a lot on standing? Mine goes up by 0.2.
As for the testers, the way to use them is to start with the one labelled just pH. If that shows the highest colour, use the high range pH one. There is an overlap, my pH falls in this overlap so I call my water 7.5. With all the testers, if the value is off the top (or bottom) of the scale, the colour still shows as the top (or bottom) colour.
Unless the pH change on standing is huge, you don't need to let water stand before adding it to the tank during a water change.