A quality torch helps to solder. Propane works, but I like MAPP gas--it's better with non-lead solders.
Pipe is rigid and goes by inside diameter. Tubing is soft can be bent and goes by outside diameter. 1/2” pipe and tubing will not fit together without adapters.
Make sure to use non lead solder and flux that is made for potable water.
Last, prior to soldering clean the outside of the pipe inside of the couplers , or fittings with a fine sandpaper or plumbers abrasive cloth to remove the varnish.
A tip: if your pipe has water in it the water will vaporize and cause leaks. Take some white bread remove the crust and stuff the bread in the side that had water. Once fully assembled remove any aerators and flow water to remove the bread.